二分搜索实例 ，先排序，算出每一个石头的间隔，从l和最小间隔中二分找答案

#include <iostream>#include <algorithm>using namespace std;int a[50010],n,m;bool cmp(int a,int b){    return a<b;}int test(int D){   int i,t=0,k=0;    for (i=0;i<n+1;i++)    {        t+=a[i];        if (t<D) k++;        else t=0;    }    if (k>m) return 0;    else return 1;}int main(){    int l,mid=0;    cin>>l>>n>>m;    for(int i=1;i<=n;i++){        cin>>a[i];    }    a[0]=0;    a[n+1]=l;    sort(a,a+n+1,cmp);    int h=a[1];    for(int i=0;i<=n;i++){        a[i]=a[i+1]-a[i];        if(a[i]<h)h=a[i];    }    while(l-h>1){        mid=(l+h)/2;        if(test(mid))h=mid;        else l=mid;    }    if(test(h+1))h++;    cout<<h;    return 0;}