hdu5323 给出左右边界，求出线段树最小的大小（暴力dfs搜索）

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#pragma comment(linker, "/STACK:102400000,102400000")#include <iostream>#include<stdio.h>#include<string.h>#include<vector>#include<algorithm>#include<cmath>#include<map>#include<queue>#define lson l,m,rt<<1#define rson m+1,r,rt<<1 | 1#define lowbit(x) x&(-x)using namespace std;const int N=1e5+10;long long INF=-1e15;int T,n,m,k;const int MOD=1e9+7;long long ans;void dfs(long long l,long long r){    if(ans && r>ans) return;    if(l<1) return;    if(l==1){        if(ans) ans=min(ans,r);        else ans=r;        return;    }    if(2*l<r+2) return;    int m=r-l+1;    if(l-m-1>0) dfs(l-m-1,r);    dfs(l-m,r);    dfs(l,r+m);    if(m>1) dfs(l,r+m-1);}int main(){#ifndef  ONLINE_JUDGE freopen("aaa","r",stdin);#endif    int T;    int L,R;    while(~scanf("%d%d",&L,&R)){         ans=0;         L++;R++;         dfs(L,R);          if(0==ans) ans=-1;          else ans--;          printf("%I64d\n",ans);    }    return 0;}

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