pat 1046 Shortest Distance

来源：互联网发布：疯狂的淘宝美工助手编辑：程序博客网时间：2024/06/04 19:00

题意是求一个环上的两点之间最短距离，纯粹模拟，最后一点超时，过不了。后来经人提示，不用保存各点的值，只要保存从起点到该点的值，即可。

代码：

//1046 18:30 -19:14#include<stdio.h>const int NUM=200008;int a[NUM];int main(){int n,i,m,x,y,j;//freopen("C:\\Documents and Settings\\Administrator\\桌面\\input.txt","r",stdin);scanf("%d",&n);int ans=0,temp,suma=0;for(i=1;i<=n;i++){scanf("%d",&a[i]);a[i+n]=a[i];ans+=a[i];}scanf("%d",&m);while(m--){suma=0;scanf("%d%d",&x,&y);if(x>y){temp=y;y=x;x=temp;}if(y-x<=n-y+x){for(i=x;i<y;i++){suma+=a[i];}} else {for(i=y;i<n+x;i++){suma+=a[i];}}if(suma<=ans-suma)printf("%d\n",suma);elseprintf("%d\n",ans-suma);}return 0;}

AC代码：

//1046 18:30 -19:14#include<stdio.h>const int NUM=200008;int a[NUM];int main(){int n,i,m,x,y,j;//freopen("C:\\Documents and Settings\\Administrator\\桌面\\input.txt","r",stdin);scanf("%d",&n);int ans=0,temp,suma=0;a[0]=0;for(i=1;i<=n;i++){scanf("%d",&a[i]);ans+=a[i];a[i]+=a[i-1];/*a[i+n]=a[i];*/}scanf("%d",&m);while(m--){suma=0;scanf("%d%d",&x,&y);if(x>y){temp=y;y=x;x=temp;}suma=a[y-1]-a[x-1];// if(y-x<=n-y+x){// suma=a[y]// } else {// for(i=y;i<n+x;i++){// suma+=a[i];// }// }if(suma<=ans-suma)printf("%d\n",suma);elseprintf("%d\n",ans-suma);}return 0;}