oj.uz

Submission #412067

# Submission time Handle Problem Language Result Execution time Memory
412067 2021-05-26T13:12:47 Z 반딧불(#7584) Pastiri (COI20_pastiri) C++17
41 / 100
 1000 ms 113204 KB 
#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

int n, k;
int par[500002], LCADB[500002][20];
vector<int> link[500002];
int minDist[500002], depth[500002];
vector<int> loc;

int ans;
int ansX[500002], ansY[500002];

void dfs_first(int x, int p=-1){
    for(auto y: link[x]){
        if(y == p) continue;
        par[y] = x;
        depth[y] = depth[x]+1;
        dfs_first(y, x);
        minDist[x] = min(minDist[x], minDist[y]+1);
    }
}

void dfs_second(int x, int p=-1, int fromUp=1e9){
    minDist[x] = min(minDist[x], fromUp);
    for(auto y: link[x]){
        if(y == p) continue;
        dfs_second(y, x, minDist[x]+1);
    }
}

int getLCA(int x, int y){
    if(depth[x] > depth[y]) swap(x, y);
    for(int d=0; d<20; d++) if((depth[y] - depth[x]) & (1<<d)) y = LCADB[y][d];
    if(x==y) return x;
    for(int d=19; d>=0; d--) if(LCADB[x][d] != LCADB[y][d]) x = LCADB[x][d], y = LCADB[y][d];
    return par[x];
}

int dist(int x, int y){
    return depth[x] + depth[y] - depth[getLCA(x, y)] * 2;
}

int main(){
    scanf("%d %d", &n, &k);
    for(int i=1; i<n; i++){
        int x, y;
        scanf("%d %d", &x, &y);
        link[x].push_back(y), link[y].push_back(x);
    }
    for(int i=1; i<=n; i++) minDist[i] = 1e9;
    for(int i=1; i<=k; i++){
        int x;
        scanf("%d", &x);
        minDist[x] = 0;
        loc.push_back(x);
    }
    dfs_first(1);
    dfs_second(1);
    for(int i=1; i<=n; i++) LCADB[i][0] = par[i];
    for(int d=1; d<20; d++) for(int i=1; i<=n; i++) LCADB[i][d] = LCADB[LCADB[i][d-1]][d-1];

    sort(loc.begin(), loc.end(), [&](int x, int y){
        return depth[x] > depth[y];
    });
    for(int i=0; i<k; i++){
        int p = loc[i];
        bool noNeed = 0;
        for(int j=0; j<ans; j++){
            if(ansY[j] == dist(ansX[j], p)){
                noNeed = 1;
                break;
            }
        }
        if(noNeed) continue;

        int tmp = p, tNew = par[p], cnt=1;
        while(tNew){
            if(minDist[tNew] == cnt){
                tmp = tNew;
                tNew = par[tNew];
                cnt++;
            }
            else break;
        }

        ansX[ans] = tmp;
        ansY[ans] = cnt-1;
        ans++;
    }

    printf("%d\n", ans);
    for(int i=0; i<ans; i++) printf("%d ", ansX[i]);
}

Compilation message

pastiri.cpp: In function 'int main()':
pastiri.cpp:47:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   47 |     scanf("%d %d", &n, &k);
      |     ~~~~~^~~~~~~~~~~~~~~~~
pastiri.cpp:50:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   50 |         scanf("%d %d", &x, &y);
      |         ~~~~~^~~~~~~~~~~~~~~~~
pastiri.cpp:56:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   56 |         scanf("%d", &x);
      |         ~~~~~^~~~~~~~~~

Subtask #1
0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 358 ms 111744 KB Output is correct
2 Correct 388 ms 111816 KB Output is correct
3 Correct 435 ms 111824 KB Output is correct
4 Execution timed out 1083 ms 113204 KB Time limit exceeded

Subtask #2
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 14 ms 12620 KB Output is correct
2 Correct 11 ms 12620 KB Output is correct
3 Correct 637 ms 79228 KB Output is correct
4 Correct 612 ms 81680 KB Output is correct
5 Correct 754 ms 79336 KB Output is correct
6 Correct 794 ms 82816 KB Output is correct

Subtask #3
23.0 / 23.0

# Verdict Execution time Memory Grader output
1 Correct 11 ms 12236 KB Output is correct
2 Correct 10 ms 12348 KB Output is correct
3 Correct 22 ms 12364 KB Output is correct
4 Correct 24 ms 12308 KB Output is correct
5 Correct 21 ms 12364 KB Output is correct
6 Correct 23 ms 12364 KB Output is correct
7 Correct 9 ms 12264 KB Output is correct
8 Correct 10 ms 12236 KB Output is correct
9 Correct 10 ms 12236 KB Output is correct
10 Correct 12 ms 12328 KB Output is correct
11 Correct 9 ms 12236 KB Output is correct
12 Correct 9 ms 12236 KB Output is correct
13 Correct 16 ms 12324 KB Output is correct
14 Correct 17 ms 12332 KB Output is correct
15 Correct 20 ms 12372 KB Output is correct

Subtask #4
0 / 51.0

# Verdict Execution time Memory Grader output
1 Execution timed out 1092 ms 73728 KB Time limit exceeded
2 Halted 0 ms 0 KB -