poj 1040 Transportation 深搜剪枝

//poj 1040//sep9#include <iostream>using namespace std;int n,m,order_num,ans;struct Order{int s,t,num,val;}orders[32];int passengers[16],most_earn[32];void dfs(int cur,int sum_value){if(cur>=order_num){ans=max(ans,sum_value);return ;}if(sum_value+most_earn[cur]<=ans) return ;dfs(cur+1,sum_value);bool success=true;for(int i=orders[cur].s;i<orders[cur].t;++i)if(passengers[i]+orders[cur].num>n){success=false;break;}if(success){for(int i=orders[cur].s;i<orders[cur].t;++i) passengers[i]+=orders[cur].num;dfs(cur+1,sum_value+orders[cur].val);for(int i=orders[cur].s;i<orders[cur].t;++i) passengers[i]-=orders[cur].num;}}int main(){while(scanf("%d%d%d",&n,&m,&order_num)==3){if(n==0&&m==0&&order_num==0) break;memset(most_earn,0,sizeof(most_earn));for(int i=0;i<order_num;++i){scanf("%d%d%d",&orders[i].s,&orders[i].t,&orders[i].num);orders[i].val=(orders[i].t-orders[i].s)*orders[i].num;}for(int i=order_num-1;i>=0;--i)most_earn[i]=most_earn[i+1]+orders[i].val;ans=0;memset(passengers,0,sizeof(passengers));dfs(0,0);printf("%d\n",ans);}return 0;}