清橙OJ A1095 回溯之教室排课
题目地址：http://www.tsinsen.com/ViewGProblem.page?gpid=A1095
//清橙OJ A1095 回溯之教室排课//http://www.tsinsen.com/ViewGProblem.page?gpid=A1095#include<stdio.h>#include<string.h>int room[9]={0,120,40,85,50,100,140,70,100};int mark[9],ans[5],demand[5],flag;void RE(int k){int i;if(k==5){flag=0;for(i=1;i<4;i++)printf("%d ",ans[i]);printf("%d\n",ans[4]);return;}for(i=1;i<=8;i++){if(mark[i]&&demand[k]<=room[i]){mark[i]=0;ans[k]=i;RE(k+1);mark[i]=1;}}}int main(){while(~scanf("%d %d %d %d",&demand[1],&demand[2],&demand[3],&demand[4])){flag=1;memset(mark,1,9*sizeof(int));RE(1);if(flag)printf("-1\n");}return 0;}