oj.uz

Submission #293069

# Submission time Handle Problem Language Result Execution time Memory
293069 2020-09-07T15:56:29 Z 반딧불(#5810) ROI16_sending (ROI16_sending) C++17
53 / 100
 898 ms 64412 KB 
#include <bits/stdc++.h>
#define LIM 20

using namespace std;

typedef long long ll;
typedef pair<int, int> pi;

struct Path{
    int x, y, idx;
    Path(){}
    Path(int x, int y, int idx): x(x), y(y), idx(idx){}

    bool operator<(const Path &r)const{
        if(x != r.x) return x < r.x;
        if(y != r.x) return y < r.y;
        return idx < r.idx;
    }
};

int n, k;
int par[200002];
vector<int> link[200002];
vector<int> centroidChild[200002];
int subTreeSize[200002];
bool centroidUsed[200002];
int centroidRoot;

int ans, ansX=1, ansY=2;

int getSubTreeSize(int x, int par){
    subTreeSize[x] = 1;
    for(auto &y: link[x]){
        if(y == par || centroidUsed[y]) continue;
        subTreeSize[x] += getSubTreeSize(y, x);
    }
    return subTreeSize[x];
}
int findCentroid(int x){
    int par = 0;
    int treeSize = getSubTreeSize(x, 0);
    while(1){
        int maxTreeSize = 0, maxTreeIdx = -1;
        for(auto &y: link[x]){
            if(centroidUsed[y] || y == par) continue;
            if(subTreeSize[y] > maxTreeSize) maxTreeSize = subTreeSize[y], maxTreeIdx = y;
        }
        if(maxTreeSize <= treeSize / 2){
            break;
        }
        par = x;
        x = maxTreeIdx;
    }
    centroidUsed[x] = 1;
    for(auto &y: link[x]){
        if(centroidUsed[y]) continue;
        int tmp = findCentroid(y);
        centroidChild[x].push_back(tmp);
    }
    return x;
}

int group[200002];
int in[200002], inCnt, depth[200002], inIdx[400002];
vector<pair<int, int> > oppVec[200002];
set<pair<int, int> > sets[200002];
int sparse[400002][LIM];
int cover[400002];

void dfsGroup(int x, int groupNum, int p = 0){
    group[x] = groupNum;
    in[x] = ++inCnt, inIdx[in[x]] = x;
    vector<pair<int, int> >().swap(oppVec[x]);
    sets[x].clear();
    for(auto &y: link[x]){
        if(centroidUsed[y] || y==p) continue;
        depth[y] = depth[x]+1;
        dfsGroup(y, groupNum, x);

        inIdx[++inCnt] = x;
    }
}

inline int LCAdepth(int x, int y){
    x = in[x], y = in[y];
    if(x>y) swap(x, y);
    int d = cover[y-x];
    return min(sparse[x][d], sparse[y-(1<<d)+1][d]);
}

inline void put(int x, pair<int, int> p){
    auto it = sets[x].lower_bound(p);
    if(it != sets[x].end()){
        int tmp = depth[x] + LCAdepth(p.first, it->first);
        if(tmp > ans) ans = tmp, ansX = p.second, ansY = it->second;
    }
    if(it != sets[x].begin()){
        it = prev(it);
        int tmp = depth[x] + LCAdepth(p.first, it->first);
        if(tmp > ans) ans = tmp, ansX = p.second, ansY = it->second;
    }
    sets[x].insert(p);
}

void dfsCalc(int x, int p = 0){
    int maxVal = -1, max_loc = -1;
    for(auto &y: link[x]){
        if(centroidUsed[y] || y==p) continue;
        dfsCalc(y, x);
        if(maxVal < (int)sets[y].size()) maxVal = sets[y].size(), max_loc = y;
    }

    sets[x].swap(sets[max_loc]);
    for(auto &y: link[x]){
        if(centroidUsed[y] || y==p || y==max_loc) continue;
        for(auto p: sets[y]) put(x, p);
        sets[y].clear();
    }
    for(auto p: oppVec[x]){
        put(x, p);
    }
}

void findAnswer(int c, vector<Path> &ust){
    vector<int> nearChild;
    vector<vector<pi> > groupVec;
    vector<vector<Path> > propVec;
    int s;

    for(auto &y: link[c]){
        if(centroidUsed[y]) continue;
        depth[y] = 1; nearChild.push_back(y);
    }
    centroidUsed[c] = 1;
    if(nearChild.empty() || ust.size() <= 1) return;
    s = (int)nearChild.size();
    groupVec.resize(s), propVec.resize(s);

    inCnt = depth[c] = 0;
    for(int i=0; i<s; i++){
        dfsGroup(nearChild[i], i);
        inIdx[++inCnt] = c;
    }
    for(int i=inCnt; i>=1; i--){
        sparse[i][0] = depth[inIdx[i]];
        for(int j=1; i+(1<<j)<=inCnt; j++){
            sparse[i][j] = min(sparse[i][j-1], sparse[i+(1<<(j-1))][j-1]);
        }
    }

    for(auto p: ust){
        if(p.x != c && p.y != c && group[p.x] == group[p.y]){
            propVec[group[p.x]].push_back(Path(p.x, p.y, p.idx));
            continue;
        }
        if(p.x != c) groupVec[group[p.x]].push_back({in[p.x], p.idx});
        if(p.y != c) groupVec[group[p.y]].push_back({in[p.y], p.idx});

        if(p.x != c && p.y != c){
            oppVec[p.x].push_back({p.y, p.idx});
            oppVec[p.y].push_back({p.x, p.idx});
        }
    }

    for(int i=0; i<s; i++){ /// check when common subtree is only one
        sort(groupVec[i].begin(), groupVec[i].end());
        for(int j=0; j<(int)groupVec[i].size()-1; j++){
            int tmp = LCAdepth(inIdx[groupVec[i][j].first], inIdx[groupVec[i][j+1].first]);
            if(ans < tmp){
                ans = tmp, ansX = groupVec[i][j].second, ansY = groupVec[i][j+1].second;
            }
        }

        for(int j=0; j<(int)groupVec[i].size(); j++){
            if(j && groupVec[i][j].first == groupVec[i][j-1].first) continue;
            int tmp1 = nearChild[i], tmp2 = inIdx[groupVec[i][j].first];
            if(tmp1 != tmp2) propVec[i].push_back(Path(tmp1, tmp2, groupVec[i][j].second));
        }
    }

    /// check when common subtree is two
    for(int i=0; i<s; i++){
        dfsCalc(nearChild[i]);
    }

    vector<int>().swap(nearChild);
    for(auto &x: groupVec) vector<pi>().swap(x);
    vector<vector<pi> >().swap(groupVec);

    /// propagate to childs
    for(auto &chd: centroidChild[c]){
        findAnswer(chd, propVec[group[chd]]);
        vector<Path>().swap(propVec[group[chd]]);
    }
}

bool endChk[200002];

int main(){
    for(int i=1; i<=400000; i++) cover[i] = cover[(i-1)/2]+1;

    scanf("%d %d", &n, &k);

    for(int i=2; i<=n; i++){
        scanf("%d", &par[i]);
        link[i].push_back(par[i]);
        link[par[i]].push_back(i);
    }
    centroidRoot = findCentroid(1);
    memset(centroidUsed, 0, sizeof(centroidUsed));

    vector<Path> st;
    for(int i=1; i<=k; i++){
        int x, y;
        scanf("%d %d", &x, &y);
        endChk[x] = endChk[y] = 1;
        st.push_back(Path(x, y, i));
    }

    findAnswer(centroidRoot, st);
    printf("%d\n%d %d", ans, ansX, ansY);
}

Compilation message

sending.cpp: In function 'int main()':
sending.cpp:202:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  202 |     scanf("%d %d", &n, &k);
      |     ~~~~~^~~~~~~~~~~~~~~~~
sending.cpp:205:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  205 |         scanf("%d", &par[i]);
      |         ~~~~~^~~~~~~~~~~~~~~
sending.cpp:215:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  215 |         scanf("%d %d", &x, &y);
      |         ~~~~~^~~~~~~~~~~~~~~~~

Subtask #1
29.0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 19 ms 25600 KB Output is correct
2 Correct 19 ms 25600 KB Output is correct
3 Correct 20 ms 25600 KB Output is correct
4 Correct 19 ms 25600 KB Output is correct
5 Correct 20 ms 25600 KB Output is correct
6 Correct 17 ms 25600 KB Output is correct
7 Correct 21 ms 25668 KB Output is correct
8 Correct 20 ms 25600 KB Output is correct
9 Correct 18 ms 25600 KB Output is correct
10 Correct 18 ms 25600 KB Output is correct
11 Correct 19 ms 25668 KB Output is correct
12 Correct 20 ms 25600 KB Output is correct
13 Correct 18 ms 25600 KB Output is correct
14 Correct 19 ms 25600 KB Output is correct
15 Correct 18 ms 25600 KB Output is correct
16 Correct 21 ms 25600 KB Output is correct
17 Correct 18 ms 25600 KB Output is correct
18 Correct 18 ms 25600 KB Output is correct
19 Correct 17 ms 25600 KB Output is correct

Subtask #2
12.0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 19 ms 25600 KB Output is correct
2 Correct 19 ms 25600 KB Output is correct
3 Correct 20 ms 25600 KB Output is correct
4 Correct 19 ms 25600 KB Output is correct
5 Correct 20 ms 25600 KB Output is correct
6 Correct 17 ms 25600 KB Output is correct
7 Correct 21 ms 25668 KB Output is correct
8 Correct 20 ms 25600 KB Output is correct
9 Correct 18 ms 25600 KB Output is correct
10 Correct 18 ms 25600 KB Output is correct
11 Correct 19 ms 25668 KB Output is correct
12 Correct 20 ms 25600 KB Output is correct
13 Correct 18 ms 25600 KB Output is correct
14 Correct 19 ms 25600 KB Output is correct
15 Correct 18 ms 25600 KB Output is correct
16 Correct 21 ms 25600 KB Output is correct
17 Correct 18 ms 25600 KB Output is correct
18 Correct 18 ms 25600 KB Output is correct
19 Correct 17 ms 25600 KB Output is correct
20 Correct 28 ms 26744 KB Output is correct
21 Correct 36 ms 26744 KB Output is correct
22 Correct 30 ms 27008 KB Output is correct
23 Correct 40 ms 27028 KB Output is correct
24 Correct 30 ms 26880 KB Output is correct
25 Correct 21 ms 26880 KB Output is correct
26 Correct 31 ms 27008 KB Output is correct
27 Correct 23 ms 26624 KB Output is correct
28 Correct 27 ms 26752 KB Output is correct
29 Correct 21 ms 27136 KB Output is correct
30 Correct 26 ms 27008 KB Output is correct
31 Correct 25 ms 27152 KB Output is correct
32 Correct 31 ms 27008 KB Output is correct
33 Correct 25 ms 27008 KB Output is correct

Subtask #3
0 / 7.0

# Verdict Execution time Memory Grader output
1 Correct 19 ms 25600 KB Output is correct
2 Correct 19 ms 25600 KB Output is correct
3 Correct 20 ms 25600 KB Output is correct
4 Correct 19 ms 25600 KB Output is correct
5 Correct 20 ms 25600 KB Output is correct
6 Correct 17 ms 25600 KB Output is correct
7 Correct 21 ms 25668 KB Output is correct
8 Correct 20 ms 25600 KB Output is correct
9 Correct 18 ms 25600 KB Output is correct
10 Correct 18 ms 25600 KB Output is correct
11 Correct 19 ms 25668 KB Output is correct
12 Correct 20 ms 25600 KB Output is correct
13 Correct 18 ms 25600 KB Output is correct
14 Correct 19 ms 25600 KB Output is correct
15 Correct 18 ms 25600 KB Output is correct
16 Correct 21 ms 25600 KB Output is correct
17 Correct 18 ms 25600 KB Output is correct
18 Correct 18 ms 25600 KB Output is correct
19 Correct 17 ms 25600 KB Output is correct
20 Correct 28 ms 26744 KB Output is correct
21 Correct 36 ms 26744 KB Output is correct
22 Correct 30 ms 27008 KB Output is correct
23 Correct 40 ms 27028 KB Output is correct
24 Correct 30 ms 26880 KB Output is correct
25 Correct 21 ms 26880 KB Output is correct
26 Correct 31 ms 27008 KB Output is correct
27 Correct 23 ms 26624 KB Output is correct
28 Correct 27 ms 26752 KB Output is correct
29 Correct 21 ms 27136 KB Output is correct
30 Correct 26 ms 27008 KB Output is correct
31 Correct 25 ms 27152 KB Output is correct
32 Correct 31 ms 27008 KB Output is correct
33 Correct 25 ms 27008 KB Output is correct
34 Correct 373 ms 49092 KB Output is correct
35 Incorrect 430 ms 49144 KB Output isn't correct
36 Halted 0 ms 0 KB -

Subtask #4
0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 19 ms 25600 KB Output is correct
2 Correct 19 ms 25600 KB Output is correct
3 Correct 20 ms 25600 KB Output is correct
4 Correct 19 ms 25600 KB Output is correct
5 Correct 20 ms 25600 KB Output is correct
6 Correct 17 ms 25600 KB Output is correct
7 Correct 21 ms 25668 KB Output is correct
8 Correct 20 ms 25600 KB Output is correct
9 Correct 18 ms 25600 KB Output is correct
10 Correct 18 ms 25600 KB Output is correct
11 Correct 19 ms 25668 KB Output is correct
12 Correct 20 ms 25600 KB Output is correct
13 Correct 18 ms 25600 KB Output is correct
14 Correct 19 ms 25600 KB Output is correct
15 Correct 18 ms 25600 KB Output is correct
16 Correct 21 ms 25600 KB Output is correct
17 Correct 18 ms 25600 KB Output is correct
18 Correct 18 ms 25600 KB Output is correct
19 Correct 17 ms 25600 KB Output is correct
20 Correct 28 ms 26744 KB Output is correct
21 Correct 36 ms 26744 KB Output is correct
22 Correct 30 ms 27008 KB Output is correct
23 Correct 40 ms 27028 KB Output is correct
24 Correct 30 ms 26880 KB Output is correct
25 Correct 21 ms 26880 KB Output is correct
26 Correct 31 ms 27008 KB Output is correct
27 Correct 23 ms 26624 KB Output is correct
28 Correct 27 ms 26752 KB Output is correct
29 Correct 21 ms 27136 KB Output is correct
30 Correct 26 ms 27008 KB Output is correct
31 Correct 25 ms 27152 KB Output is correct
32 Correct 31 ms 27008 KB Output is correct
33 Correct 25 ms 27008 KB Output is correct
34 Correct 373 ms 49092 KB Output is correct
35 Incorrect 430 ms 49144 KB Output isn't correct
36 Halted 0 ms 0 KB -

Subtask #5
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 436 ms 54252 KB Output is correct
2 Correct 898 ms 60364 KB Output is correct
3 Incorrect 803 ms 60312 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #6
12.0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 524 ms 54000 KB Output is correct
2 Correct 668 ms 53876 KB Output is correct
3 Correct 703 ms 63084 KB Output is correct
4 Correct 665 ms 62832 KB Output is correct
5 Correct 632 ms 58480 KB Output is correct
6 Correct 93 ms 54896 KB Output is correct
7 Correct 703 ms 63120 KB Output is correct
8 Correct 159 ms 51988 KB Output is correct
9 Correct 286 ms 51024 KB Output is correct
10 Correct 154 ms 63216 KB Output is correct
11 Correct 437 ms 64412 KB Output is correct
12 Correct 417 ms 64124 KB Output is correct
13 Correct 744 ms 63728 KB Output is correct

Subtask #7
0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 19 ms 25600 KB Output is correct
2 Correct 19 ms 25600 KB Output is correct
3 Correct 20 ms 25600 KB Output is correct
4 Correct 19 ms 25600 KB Output is correct
5 Correct 20 ms 25600 KB Output is correct
6 Correct 17 ms 25600 KB Output is correct
7 Correct 21 ms 25668 KB Output is correct
8 Correct 20 ms 25600 KB Output is correct
9 Correct 18 ms 25600 KB Output is correct
10 Correct 18 ms 25600 KB Output is correct
11 Correct 19 ms 25668 KB Output is correct
12 Correct 20 ms 25600 KB Output is correct
13 Correct 18 ms 25600 KB Output is correct
14 Correct 19 ms 25600 KB Output is correct
15 Correct 18 ms 25600 KB Output is correct
16 Correct 21 ms 25600 KB Output is correct
17 Correct 18 ms 25600 KB Output is correct
18 Correct 18 ms 25600 KB Output is correct
19 Correct 17 ms 25600 KB Output is correct
20 Correct 28 ms 26744 KB Output is correct
21 Correct 36 ms 26744 KB Output is correct
22 Correct 30 ms 27008 KB Output is correct
23 Correct 40 ms 27028 KB Output is correct
24 Correct 30 ms 26880 KB Output is correct
25 Correct 21 ms 26880 KB Output is correct
26 Correct 31 ms 27008 KB Output is correct
27 Correct 23 ms 26624 KB Output is correct
28 Correct 27 ms 26752 KB Output is correct
29 Correct 21 ms 27136 KB Output is correct
30 Correct 26 ms 27008 KB Output is correct
31 Correct 25 ms 27152 KB Output is correct
32 Correct 31 ms 27008 KB Output is correct
33 Correct 25 ms 27008 KB Output is correct
34 Correct 373 ms 49092 KB Output is correct
35 Incorrect 430 ms 49144 KB Output isn't correct
36 Halted 0 ms 0 KB -

Subtask #8
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 19 ms 25600 KB Output is correct
2 Correct 19 ms 25600 KB Output is correct
3 Correct 20 ms 25600 KB Output is correct
4 Correct 19 ms 25600 KB Output is correct
5 Correct 20 ms 25600 KB Output is correct
6 Correct 17 ms 25600 KB Output is correct
7 Correct 21 ms 25668 KB Output is correct
8 Correct 20 ms 25600 KB Output is correct
9 Correct 18 ms 25600 KB Output is correct
10 Correct 18 ms 25600 KB Output is correct
11 Correct 19 ms 25668 KB Output is correct
12 Correct 20 ms 25600 KB Output is correct
13 Correct 18 ms 25600 KB Output is correct
14 Correct 19 ms 25600 KB Output is correct
15 Correct 18 ms 25600 KB Output is correct
16 Correct 21 ms 25600 KB Output is correct
17 Correct 18 ms 25600 KB Output is correct
18 Correct 18 ms 25600 KB Output is correct
19 Correct 17 ms 25600 KB Output is correct
20 Correct 28 ms 26744 KB Output is correct
21 Correct 36 ms 26744 KB Output is correct
22 Correct 30 ms 27008 KB Output is correct
23 Correct 40 ms 27028 KB Output is correct
24 Correct 30 ms 26880 KB Output is correct
25 Correct 21 ms 26880 KB Output is correct
26 Correct 31 ms 27008 KB Output is correct
27 Correct 23 ms 26624 KB Output is correct
28 Correct 27 ms 26752 KB Output is correct
29 Correct 21 ms 27136 KB Output is correct
30 Correct 26 ms 27008 KB Output is correct
31 Correct 25 ms 27152 KB Output is correct
32 Correct 31 ms 27008 KB Output is correct
33 Correct 25 ms 27008 KB Output is correct
34 Correct 373 ms 49092 KB Output is correct
35 Incorrect 430 ms 49144 KB Output isn't correct
36 Halted 0 ms 0 KB -