Codeforces 773D Perishable Roads 最短路 （看题解）

Perishable Roads

智商题， 不会啊。。 

贴个官方题解

https://codeforces.com/blog/entry/51883

#include<bits/stdc++.h>
#define LL long long
#define LD long double
#define ull unsigned long long
#define fi first
#define se second
#define mk make_pair
#define PLL pair<LL, LL>
#define PLI pair<LL, int>
#define PII pair<int, int>
#define SZ(x) ((int)x.size())
#define ALL(x) (x).begin(), (x).end()
#define fio ios::sync_with_stdio(false); cin.tie(0);

using namespace std;

const int N = 2000 + 7;
const int inf = 0x3f3f3f3f;
const LL INF = 0x3f3f3f3f3f3f3f3f;
const int mod = 1e9 + 7;
const double eps = 1e-8;
const double PI = acos(-1);

template<class T, class S> inline void add(T &a, S b) {a += b; if(a >= mod) a -= mod;}
template<class T, class S> inline void sub(T &a, S b) {a -= b; if(a < 0) a += mod;}
template<class T, class S> inline bool chkmax(T &a, S b) {return a < b ? a = b, true : false;}
template<class T, class S> inline bool chkmin(T &a, S b) {return a > b ? a = b, true : false;}

int n, mine = inf, G[N][N], d[N];
bool vis[N];

int main() {
    scanf("%d", &n);
    for(int i = 1; i <= n; i++) {
        for(int j = i + 1; j <= n; j++) {
            scanf("%d", &G[i][j]);
            G[j][i] = G[i][j];
            chkmin(mine, G[i][j]);
        }
    }
    for(int i = 1; i <= n; i++) {
        for(int j = i + 1; j <= n; j++) {
            G[i][j] -= mine;
            G[j][i] -= mine;
        }
    }
    for(int i = 1; i <= n; i++) {
        d[i] = inf;
        for(int j = 1; j <= n; j++) {
            if(i != j) {
                chkmin(d[i], G[i][j] << 1);
            }
        }
    }
    d[0] = inf;
    for(int i = 1; i <= n; i++) {
        int p = 0;
        for(int j = 1; j <= n; j++) {
            if(!vis[j] && d[j] < d[p]) {
                p = j;
            }
        }
        for(int j = 1; j <= n; j++) {
            chkmin(d[j], d[p] + G[p][j]);
        }
        vis[p] = true;
    }
    for(int i = 1; i <= n; i++) printf("%lld
", 1LL * (n - 1) * mine + d[i]);
    return 0;
}

/*
*/