poj 2182 lost cows 树状数组，二分

线段树做法

http://www.cnblogs.com/wuyiqi/archive/2011/12/21/2295391.html

从后往前操作

#include<cstdio>
#include<cstring>
const int maxn = 80001;
int a[maxn],c[maxn],ans[maxn],n;
int lowbit(int x){
    return x&-x;
}
void update(int x,int d){
    for(;x<maxn;x+=lowbit(x))
        c[x]+=d;
}
int sum(int x){
    int ans=0;
    for(;x>0;x-=lowbit(x))
        ans+=c[x];
    return ans;
}
int bin(int num){
    int l=1,r=n,mid,tmp,best;
    while(l<=r){
        mid=(l+r)>>1;
        tmp=sum(mid);
        if(tmp>=num){
            best=mid;
            r=mid-1;
        }
        else l=mid+1;
    }
    return best;
}
int main(){
    int i,j;
while(~scanf("%d",&n)){
    memset(c,0,sizeof(c));
    a[1]=0;update(1,1);
    for(i=2;i<=n;i++){
        scanf("%d",&a[i]);
        update(i,1);
    }
    for(i=n;i>=1;i--){
        int pos=bin(a[i]+1);
        ans[i]=pos;
        update(pos,-1);
    }
    for(i=1;i<=n;i++)  printf("%d\n",ans[i]);
  }
}