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답안 #292960

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
292960 2020-09-07T15:02:23 Z 반딧불(#5810) 서류 전달 (ROI16_sending) C++17
41 / 100
 1288 ms 524292 KB 
#include <bits/stdc++.h>
#define LIM 19

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 par = 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==par) 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]);
}

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 par = 0){
    int minVal = INT_MAX, min_loc = -1;
    for(auto &y: link[x]){
        if(centroidUsed[y] || y==par) continue;
        dfsCalc(y, x);
        if(minVal > (int)sets[y].size()) minVal = sets[y].size(), min_loc = y;
    }

    sets[x] = sets[min_loc];
    for(auto &y: link[x]){
        if(centroidUsed[y] || y==par || y==min_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);
    }
    if(nearChild.empty()) return;
    centroidUsed[c] = 1;
    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){ /// insert into map
            int tmp1 = group[p.x], tmp2 = group[p.y];
            if(tmp1 > tmp2) swap(tmp1, tmp2);
            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 tmpMin = INT_MAX;
            for(int x=groupVec[i][j].first; x<=groupVec[i][j+1].first; x++) tmpMin = min(tmpMin, depth[inIdx[x]]);
            if(ans < tmpMin){
                ans = tmpMin, 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(min(tmp1, tmp2), max(tmp1, tmp2), groupVec[i][j].second));
        }
    }

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

    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]]);
    }
}

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);
        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:204:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  204 |         scanf("%d", &par[i]);
      |         ~~~~~^~~~~~~~~~~~~~~
sending.cpp:214:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  214 |         scanf("%d %d", &x, &y);
      |         ~~~~~^~~~~~~~~~~~~~~~~

Subtask #1
29.0 / 29.0

# 결과 실행 시간 메모리 Grader output
1 Correct 17 ms 25600 KB Output is correct
2 Correct 17 ms 25600 KB Output is correct
3 Correct 18 ms 25600 KB Output is correct
4 Correct 18 ms 25600 KB Output is correct
5 Correct 17 ms 25600 KB Output is correct
6 Correct 18 ms 25600 KB Output is correct
7 Correct 18 ms 25600 KB Output is correct
8 Correct 18 ms 25728 KB Output is correct
9 Correct 19 ms 25728 KB Output is correct
10 Correct 18 ms 25600 KB Output is correct
11 Correct 18 ms 25600 KB Output is correct
12 Correct 19 ms 25728 KB Output is correct
13 Correct 18 ms 25600 KB Output is correct
14 Correct 18 ms 25600 KB Output is correct
15 Correct 18 ms 25984 KB Output is correct
16 Correct 19 ms 25728 KB Output is correct
17 Correct 18 ms 25728 KB Output is correct
18 Correct 19 ms 25728 KB Output is correct
19 Correct 20 ms 25600 KB Output is correct

Subtask #2
12.0 / 12.0

# 결과 실행 시간 메모리 Grader output
1 Correct 17 ms 25600 KB Output is correct
2 Correct 17 ms 25600 KB Output is correct
3 Correct 18 ms 25600 KB Output is correct
4 Correct 18 ms 25600 KB Output is correct
5 Correct 17 ms 25600 KB Output is correct
6 Correct 18 ms 25600 KB Output is correct
7 Correct 18 ms 25600 KB Output is correct
8 Correct 18 ms 25728 KB Output is correct
9 Correct 19 ms 25728 KB Output is correct
10 Correct 18 ms 25600 KB Output is correct
11 Correct 18 ms 25600 KB Output is correct
12 Correct 19 ms 25728 KB Output is correct
13 Correct 18 ms 25600 KB Output is correct
14 Correct 18 ms 25600 KB Output is correct
15 Correct 18 ms 25984 KB Output is correct
16 Correct 19 ms 25728 KB Output is correct
17 Correct 18 ms 25728 KB Output is correct
18 Correct 19 ms 25728 KB Output is correct
19 Correct 20 ms 25600 KB Output is correct
20 Correct 31 ms 26752 KB Output is correct
21 Correct 39 ms 27008 KB Output is correct
22 Correct 266 ms 73372 KB Output is correct
23 Correct 276 ms 75000 KB Output is correct
24 Correct 242 ms 27000 KB Output is correct
25 Correct 21 ms 27008 KB Output is correct
26 Correct 264 ms 73592 KB Output is correct
27 Correct 23 ms 26624 KB Output is correct
28 Correct 29 ms 26880 KB Output is correct
29 Correct 128 ms 77436 KB Output is correct
30 Correct 339 ms 97528 KB Output is correct
31 Correct 226 ms 72568 KB Output is correct
32 Correct 247 ms 68472 KB Output is correct
33 Correct 76 ms 31608 KB Output is correct

Subtask #3
0 / 7.0

# 결과 실행 시간 메모리 Grader output
1 Correct 17 ms 25600 KB Output is correct
2 Correct 17 ms 25600 KB Output is correct
3 Correct 18 ms 25600 KB Output is correct
4 Correct 18 ms 25600 KB Output is correct
5 Correct 17 ms 25600 KB Output is correct
6 Correct 18 ms 25600 KB Output is correct
7 Correct 18 ms 25600 KB Output is correct
8 Correct 18 ms 25728 KB Output is correct
9 Correct 19 ms 25728 KB Output is correct
10 Correct 18 ms 25600 KB Output is correct
11 Correct 18 ms 25600 KB Output is correct
12 Correct 19 ms 25728 KB Output is correct
13 Correct 18 ms 25600 KB Output is correct
14 Correct 18 ms 25600 KB Output is correct
15 Correct 18 ms 25984 KB Output is correct
16 Correct 19 ms 25728 KB Output is correct
17 Correct 18 ms 25728 KB Output is correct
18 Correct 19 ms 25728 KB Output is correct
19 Correct 20 ms 25600 KB Output is correct
20 Correct 31 ms 26752 KB Output is correct
21 Correct 39 ms 27008 KB Output is correct
22 Correct 266 ms 73372 KB Output is correct
23 Correct 276 ms 75000 KB Output is correct
24 Correct 242 ms 27000 KB Output is correct
25 Correct 21 ms 27008 KB Output is correct
26 Correct 264 ms 73592 KB Output is correct
27 Correct 23 ms 26624 KB Output is correct
28 Correct 29 ms 26880 KB Output is correct
29 Correct 128 ms 77436 KB Output is correct
30 Correct 339 ms 97528 KB Output is correct
31 Correct 226 ms 72568 KB Output is correct
32 Correct 247 ms 68472 KB Output is correct
33 Correct 76 ms 31608 KB Output is correct
34 Correct 442 ms 48248 KB Output is correct
35 Incorrect 505 ms 48696 KB Output isn't correct
36 Halted 0 ms 0 KB -

Subtask #4
0 / 8.0

# 결과 실행 시간 메모리 Grader output
1 Correct 17 ms 25600 KB Output is correct
2 Correct 17 ms 25600 KB Output is correct
3 Correct 18 ms 25600 KB Output is correct
4 Correct 18 ms 25600 KB Output is correct
5 Correct 17 ms 25600 KB Output is correct
6 Correct 18 ms 25600 KB Output is correct
7 Correct 18 ms 25600 KB Output is correct
8 Correct 18 ms 25728 KB Output is correct
9 Correct 19 ms 25728 KB Output is correct
10 Correct 18 ms 25600 KB Output is correct
11 Correct 18 ms 25600 KB Output is correct
12 Correct 19 ms 25728 KB Output is correct
13 Correct 18 ms 25600 KB Output is correct
14 Correct 18 ms 25600 KB Output is correct
15 Correct 18 ms 25984 KB Output is correct
16 Correct 19 ms 25728 KB Output is correct
17 Correct 18 ms 25728 KB Output is correct
18 Correct 19 ms 25728 KB Output is correct
19 Correct 20 ms 25600 KB Output is correct
20 Correct 31 ms 26752 KB Output is correct
21 Correct 39 ms 27008 KB Output is correct
22 Correct 266 ms 73372 KB Output is correct
23 Correct 276 ms 75000 KB Output is correct
24 Correct 242 ms 27000 KB Output is correct
25 Correct 21 ms 27008 KB Output is correct
26 Correct 264 ms 73592 KB Output is correct
27 Correct 23 ms 26624 KB Output is correct
28 Correct 29 ms 26880 KB Output is correct
29 Correct 128 ms 77436 KB Output is correct
30 Correct 339 ms 97528 KB Output is correct
31 Correct 226 ms 72568 KB Output is correct
32 Correct 247 ms 68472 KB Output is correct
33 Correct 76 ms 31608 KB Output is correct
34 Correct 442 ms 48248 KB Output is correct
35 Incorrect 505 ms 48696 KB Output isn't correct
36 Halted 0 ms 0 KB -

Subtask #5
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 509 ms 57324 KB Output is correct
2 Correct 1288 ms 60724 KB Output is correct
3 Incorrect 1061 ms 60696 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #6
0 / 12.0

# 결과 실행 시간 메모리 Grader output
1 Correct 612 ms 53868 KB Output is correct
2 Correct 946 ms 55572 KB Output is correct
3 Runtime error 705 ms 524292 KB Execution killed with signal 9
4 Halted 0 ms 0 KB -

Subtask #7
0 / 12.0

# 결과 실행 시간 메모리 Grader output
1 Correct 17 ms 25600 KB Output is correct
2 Correct 17 ms 25600 KB Output is correct
3 Correct 18 ms 25600 KB Output is correct
4 Correct 18 ms 25600 KB Output is correct
5 Correct 17 ms 25600 KB Output is correct
6 Correct 18 ms 25600 KB Output is correct
7 Correct 18 ms 25600 KB Output is correct
8 Correct 18 ms 25728 KB Output is correct
9 Correct 19 ms 25728 KB Output is correct
10 Correct 18 ms 25600 KB Output is correct
11 Correct 18 ms 25600 KB Output is correct
12 Correct 19 ms 25728 KB Output is correct
13 Correct 18 ms 25600 KB Output is correct
14 Correct 18 ms 25600 KB Output is correct
15 Correct 18 ms 25984 KB Output is correct
16 Correct 19 ms 25728 KB Output is correct
17 Correct 18 ms 25728 KB Output is correct
18 Correct 19 ms 25728 KB Output is correct
19 Correct 20 ms 25600 KB Output is correct
20 Correct 31 ms 26752 KB Output is correct
21 Correct 39 ms 27008 KB Output is correct
22 Correct 266 ms 73372 KB Output is correct
23 Correct 276 ms 75000 KB Output is correct
24 Correct 242 ms 27000 KB Output is correct
25 Correct 21 ms 27008 KB Output is correct
26 Correct 264 ms 73592 KB Output is correct
27 Correct 23 ms 26624 KB Output is correct
28 Correct 29 ms 26880 KB Output is correct
29 Correct 128 ms 77436 KB Output is correct
30 Correct 339 ms 97528 KB Output is correct
31 Correct 226 ms 72568 KB Output is correct
32 Correct 247 ms 68472 KB Output is correct
33 Correct 76 ms 31608 KB Output is correct
34 Correct 442 ms 48248 KB Output is correct
35 Incorrect 505 ms 48696 KB Output isn't correct
36 Halted 0 ms 0 KB -

Subtask #8
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 17 ms 25600 KB Output is correct
2 Correct 17 ms 25600 KB Output is correct
3 Correct 18 ms 25600 KB Output is correct
4 Correct 18 ms 25600 KB Output is correct
5 Correct 17 ms 25600 KB Output is correct
6 Correct 18 ms 25600 KB Output is correct
7 Correct 18 ms 25600 KB Output is correct
8 Correct 18 ms 25728 KB Output is correct
9 Correct 19 ms 25728 KB Output is correct
10 Correct 18 ms 25600 KB Output is correct
11 Correct 18 ms 25600 KB Output is correct
12 Correct 19 ms 25728 KB Output is correct
13 Correct 18 ms 25600 KB Output is correct
14 Correct 18 ms 25600 KB Output is correct
15 Correct 18 ms 25984 KB Output is correct
16 Correct 19 ms 25728 KB Output is correct
17 Correct 18 ms 25728 KB Output is correct
18 Correct 19 ms 25728 KB Output is correct
19 Correct 20 ms 25600 KB Output is correct
20 Correct 31 ms 26752 KB Output is correct
21 Correct 39 ms 27008 KB Output is correct
22 Correct 266 ms 73372 KB Output is correct
23 Correct 276 ms 75000 KB Output is correct
24 Correct 242 ms 27000 KB Output is correct
25 Correct 21 ms 27008 KB Output is correct
26 Correct 264 ms 73592 KB Output is correct
27 Correct 23 ms 26624 KB Output is correct
28 Correct 29 ms 26880 KB Output is correct
29 Correct 128 ms 77436 KB Output is correct
30 Correct 339 ms 97528 KB Output is correct
31 Correct 226 ms 72568 KB Output is correct
32 Correct 247 ms 68472 KB Output is correct
33 Correct 76 ms 31608 KB Output is correct
34 Correct 442 ms 48248 KB Output is correct
35 Incorrect 505 ms 48696 KB Output isn't correct
36 Halted 0 ms 0 KB -