hdu 5428

二分 加一下小判断

#include<stdio.h>#include<queue>#include<string.h>#include<algorithm>#include<map>#define ll long longusing namespace std;int a[2000000];int a1[2000000];int n;int j(int t){    memcpy(a1,a,sizeof(a));    for(int i=1;i<=n;i++)    {        if(a1[i]>a1[i-1])            a1[i]=max(a1[i-1]+1,a1[i]-t);        else {            if(a1[i]+t<=a1[i-1]) return 0;            a1[i]=a1[i-1]+1;        }    }    return 1;}int main(){    int t;    int jj=0;    scanf("%d",&t);    while(t--)    {       int ans;       jj++;       scanf("%d",&n);       a[0]=-10000000;       for(int i=1;i<=n;i++)        scanf("%d",&a[i]);       int l=0,r=10000000;       while(l<=r)       {           int mid=(r+l)>>1;           if(j(mid))           {//printf("%d\n",mid);               ans=mid;               r=mid-1;           }           else l=mid+1;       }       printf("Case #%d:\n",jj);       printf("%d\n",ans);    }}