圈

题目地址：http://www.51cpc.com/web/problem.php?id=4286

解法 1：

#include<iostream>
#include<map>
using namespace std;

#define LL long long
map<LL, LL> imap;
int n;

int main()
{
    ios::sync_with_stdio(false);
    while(cin>>n) {
        LL a,b;
        for(int i=0; i<n; i++) {
            cin>>a>>b;
            imap[a] += b;
        }
        
        LL ans=0, last=0;
        map<LL, LL>::iterator iter = imap.begin();
        for(; iter!=imap.end(); iter++) {
            map<LL, LL>::iterator p = ++iter;
            iter--;
            
            LL one=iter->first, two=max(iter->second, last);
            if(p == imap.end()) {
                ans = one+1;
                two = two/4 + (two%4==0?0:1);
                while(two > 1) {
                    two = two/4 + (two%4==0?0:1);
                    ans++;
                }
                break;
            }
            
            last=two;
            while(one < p->first) {
                one++;
                last = last/4 + (last%4==0?0:1);
                if(last == 1) break;
            }
        }
        cout<<ans<<endl;
        imap.clear();
    }
    
    return 0;
}

解法 2：机智的解法

#include <cstdio>
#include <iostream>
#include <cmath>
#include <algorithm>
using namespace std;
const int MAXN=2e5+5;
struct Node
{
    int w,cnt;
}data[MAXN];
int main()
{
    int n;
    while(scanf("%d",&n)!=EOF)
    {
        int ans=0;
        for(int i=0;i<n;i++)
        {
            cin>>data[i].w>>data[i].cnt;
            int tot=1;
            for(int j=data[i].w+1;;j++)
            {
                tot*=4;
                if(tot>=data[i].cnt)
                {
                    ans=max(ans,j);break;
                }
            }
        }
        cout<<ans<<endl;
    }
    ret

解法 3：这个简直超神了。。看到这个瞬间就清醒了，就是求4的多少次，特判下0的情况就行；

#include<cstdio>
#include<cmath>
int N,R=0,T,K,A;
main(){
    scanf("%d",&N);
    while(N--){
        scanf("%d%d",&K,&A);
        A=ceil(log2(A)/2);
        K+=1>A?1:A;
        R=R<K?K:R;
    }
    printf("%d",R);
}