hdu2852 树状数组+二分

hdu2852 树状数组+二分

#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
using namespace std;
const int maxn = 300300;
int c[maxn];
int lowbit(int x) {
 return x&(-x);
}
int sum(int x) {
 int s = 0;
 for(int i=x;i>0;i-=lowbit(i))
  s += c[i];
 return s;
}
int main() {
 int m;
 while(~scanf("%d",&m)) {
  memset(c,0,sizeof(c));
  while(m--) {
   int op;
   scanf("%d",&op);
   if(op == 0) {
    int x;
    scanf("%d",&x);
    for(int i=x;i<maxn;i+=lowbit(i)) c[i] ++;
   }
   else if(op==1) {
    int x;
    scanf("%d",&x);
    int s = sum(x) - sum(x-1);
    if(s) for(int i=x;i<maxn;i+=lowbit(i)) c[i] --;
    else printf("No Elment!\n");
   }
   else {
    int x , k;
    scanf("%d%d",&x,&k);
    k += sum(x);
    int l = 1 , r = maxn - 1;
    while(l < r) {
     int mid = (l + r) >> 1;
     if(sum(mid) < k) l = mid + 1;
     else r = mid;
    }
    if(sum(l) < k) printf("Not Find!\n");
    else printf("%d\n",l);
   }
  }
 }
 return 0;
}