Submission #1011474

#	Time	Username	Problem	Language	Result	Execution time	Memory
1011474		gutzzy	Shortcut (IOI16_shortcut)	C++17	0 / 100	2098 ms	860 KiB

shortcut

#include <bits/stdc++.h>
using namespace std;
const long long inf = 9223372036854775807;
vector<vector<long long>> m;

void floyd_warshall(int n){
    for(int k=0;k<n;k++){
        for(int i=0;i<2*n;i++){
            for(int j=0;j<2*n;j++){
                if((m[i][j]>m[i][k]+m[k][j]) and m[k][j]!=inf and m[i][k] != inf){
                    m[i][j] = m[i][k] + m[k][j];
                }
            }
        }
    }
    return;
}

long long diam(vector<vector<long long>> &g, int n){
    long long res = 0;
    for(int i=0;i<2*n;i++){
        for(int j=i;j<2*n;j++){
            res = max(res,g[i][j]);
        }
    }
    return res;
}

long long find_shortcut(int n, vector<int> l, vector<int> d, int c){
    m = vector<vector<long long>> (2*n,vector<long long>(2*n,inf));
    for(int i=0;i<2*n;i++) m[i][i] = 0;
    long long ans = inf;
    for(int i=0;i<n-1;i++){
        m[i][i+1] = (long long) l[i];
        m[i+1][i] = (long long) l[i];
    }
    for(int i=0;i<n;i++){
        m[i][n+i] = (long long) d[i];
        m[n+i][i] = (long long) d[i];
    }
    vector<vector<long long>> mm = m;
    floyd_warshall(n);
    ans = min(ans, diam(m,n));
    m = mm;
    for(int i=0;i<n;i++){
        for(int j=i+1;j<n;j++){
            // express railroad entre i & j
            if(m[i][j]<=c) continue;
            m[i][j] = c;
            m[j][i] = c;
            floyd_warshall(n);
            ans = min(ans, diam(m,n));
            m = mm;
        }
    }
    return ans;
}

/*

int main(){
    
    cout << find_shortcut(2, {5}, {3, 0}, 1) << endl;

    return 0;
}
*/

• Subtask 1: 0 / 9
• Subtask 2: 0 / 14
• Subtask 3: 0 / 8
• Subtask 4: 0 / 7
• Subtask 5: 0 / 33
• Subtask 6: 0 / 22
• Subtask 7: 0 / 4
• Subtask 8: 0 / 3