题意:略。
析:当时比赛真是脑残了。。。。一直想什么拓扑模板,其实并不需要么,当时脑子短路了。。。。完全可以直接根据题意写的,用优先队列
维护一下就好。最近没刷题真是落后了。。。。不说了,太水了。
代码如下:
#pragma comment(linker, "/STACK:1024000000,1024000000") #include <cstdio> #include <string> #include <cstdlib> #include <cmath> #include <iostream> #include <cstring> #include <set> #include <queue> #include <algorithm> #include <vector> #include <map> #include <cctype> #include <cmath> #include <stack> #include <sstream> #define debug() puts("++++"); #define gcd(a, b) __gcd(a, b) #define lson l,m,rt<<1 #define rson m+1,r,rt<<1|1 #define freopenr freopen("in.txt", "r", stdin) #define freopenw freopen("out.txt", "w", stdout) using namespace std; typedef long long LL; typedef unsigned long long ULL; typedef pair<int, int> P; const int INF = 0x3f3f3f3f; const LL LNF = 1e16; const double inf = 0x3f3f3f3f3f3f; const double PI = acos(-1.0); const double eps = 1e-8; const int maxn = 100000 + 10; const int mod = 1000000007; const int dr[] = {-1, 0, 1, 0}; const int dc[] = {0, 1, 0, -1}; const char *de[] = {"0000", "0001", "0010", "0011", "0100", "0101", "0110", "0111", "1000", "1001", "1010", "1011", "1100", "1101", "1110", "1111"}; int n, m; const int mon[] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}; const int monn[] = {0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}; inline bool is_in(int r, int c){ return r >= 0 && r < n && c >= 0 && c < m; } vector<int> G[maxn]; int in[maxn]; int main(){ int T; cin >> T; while(T--){ scanf("%d %d", &n, &m); for(int i = 1; i <= n; ++i) G[i].clear(); memset(in, 0, sizeof in); for(int i = 0; i < m; ++i){ int a, b; scanf("%d %d", &a, &b); G[a].push_back(b); ++in[b]; } LL ans = 0; int mmin = INF; priority_queue<int> pq; for(int i = 1; i <= n; ++i) if(!in[i]) pq.push(i); while(!pq.empty()){ int u = pq.top(); pq.pop(); mmin = min(mmin, u); ans += mmin; for(int i = 0; i < G[u].size(); ++i){ int v = G[u][i]; --in[v]; if(!in[v]) pq.push(v); } } cout << ans << endl; } return 0; }
时间: 2024-11-01 09:11:06