（p241）活动选择

#include<stdio.h>#include<limits.h>#define max 1000int GreedyActivitySelector(int s[],int f[],int ans[],int n)//贪心{int k=0,i,count=0;for (i=1;i<=n;i++)if (s[i]>=f[k]){ans[count++]=i;k=i;}return count;}int ActivitySelector(int s[],int f[],int ans[],int k,int n,int *count)//递归{int i=k+1;while ((i<=n)&&(s[i]<f[k]))i++;if (i<=n){ans[(*count)++]=i;ActivitySelector(s,f,ans,i,n,count);}return 0;}int ActivitySelector2(int s[],int f[],int n)//动态规划{int i,j,k,l;int c[max+2][max+2];for (i=0;i<=n+1;i++)for (j=0;j<=n+1;j++)c[i][j]=0;for (l=0;l<=n+1;l++)for (i=0;i<=n+1-l;i++){j=i+l;for (k=i+1;k<=j-1;k++)//注意k=0和n+1的情况if ((s[k]>=f[i])&&(f[k]<=s[j])&&(c[i][k]+c[k][j]+1>c[i][j]))c[i][j]=c[i][k]+c[k][j]+1;}for (j=0;j<=n+1;j++)printf("%3d ",j);printf("\n");for (i=0;i<=n+1;i++){for (j=0;j<i;j++)printf("    ");for (j=i;j<=n+1;j++)printf("%3d ",c[i][j]);printf("%3d\n",i);printf("\n");}return c[0][n+1];}int main(void){int f[max+2]={0,4,5,6,7,9,9,10,11,12,14,16};int s[max+2]={0,1,3,0,5,3,5,6,8,8,2,12};int ans[max];int count;int n=11;count=GreedyActivitySelector(s,f,ans,n);printf("%d\n",count);int i;for (i=0;i<count;i++)printf("%d ",ans[i]);count=0;ActivitySelector(s,f,ans,0,n,&count);printf("\n%d\n",count);for (i=0;i<count;i++)printf("%d ",ans[i]);printf("\n");s[n+1]=INT_MAX;//为了便于处理，设置一个最后开始的活动f[n+1]=INT_MAX;count=ActivitySelector2(s,f,n);printf("\n%3d\n",count);return 0;}