【關鍵路徑】hdu 4109

#include <map>#include <set>#include <list>#include <queue>#include <deque>#include <stack>#include <string>#include <time.h>#include <cstdio>#include <math.h>#include <iomanip>#include <cstdlib>#include <limits.h>#include <string.h>#include <iostream>#include <fstream>#include <algorithm>using namespace std;#define LL long long#define MIN INT_MIN#define MAX INT_MAX#define PI acos(-1.0)#define FRE freopen("input.txt","r",stdin)#define FF freopen("output.txt","w",stdout)#define N 1005struct node{    int y,w;};vector<node> v[N];int n,m;int tt[N];int in[N];void init () {    int i;    for (i = 0; i <= n; i++ ) v[i].clear();}void gao () {    int i,j;    queue<int> qq;    for (i = 0 ; i < n ; i++) {        tt[i] = 0;        if (!in[i]) {            qq.push(i);            tt[i] = 1;        }    }    while (!qq.empty()) {        int x = qq.front();        qq.pop();        for (i = 0; i < v[x].size(); i++) {            node tmp = v[x][i];            int y = tmp.y;            tt[y] = max(tt[y],tt[x] + tmp.w);            in[y]--;            if (!in[y]) {                qq.push(y);            }        }    }    int ans = 0;    for (i = 0; i < n; i++) {        ans = max(ans,tt[i]);    }    printf("%d\n",ans);}int main () {   while (scanf("%d%d",&n,&m) != EOF)  {       int i,j;       init();       memset(in,0,sizeof(in));       for (i = 0; i < m; i++) {           int a,b,c;           scanf("%d%d%d",&a,&b,&c);           in[b]++;           node tmp;           tmp.y = b;           tmp.w = c;           v[a].push_back(tmp);       }       gao();   }   return 0;}