【CF】223 Div.1 C Sereja and Brackets

水线段树。

/* 380C */
#include <iostream>
#include <string>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <vector>
#include <deque>
#include <algorithm>
#include <cstdio>
#include <cmath>
#include <ctime>
#include <cstring>
#include <climits>
#include <cctype>
#include <cassert>
#include <functional>
#include <iterator>
#include <iomanip>
using namespace std;
//#pragma comment(linker,"/STACK:102400000,1024000")

#define sti                set<int>
#define stpii            set<pair<int, int> >
#define mpii            map<int,int>
#define vi                vector<int>
#define pii                pair<int,int>
#define vpii            vector<pair<int,int> >
#define rep(i, a, n)     for (int i=a;i<n;++i)
#define per(i, a, n)     for (int i=n-1;i>=a;--i)
#define clr                clear
#define pb                 push_back
#define mp                 make_pair
#define fir                first
#define sec                second
#define all(x)             (x).begin(),(x).end()
#define SZ(x)             ((int)(x).size())
#define lson            l, mid, rt<<1
#define rson            mid+1, r, rt<<1|1

const int maxn = 1e6+5;
char s[maxn];
int ln[maxn<<2];
int rn[maxn<<2];
int L, R;

inline void PushUp(int rt) {
    int lb = rt<<1;
    int rb = (rt<<1)|1;
    int tmp = min(ln[lb], rn[rb]);
    
    ln[rt] = ln[lb] + ln[rb] - tmp;
    rn[rt] = rn[lb] + rn[rb] - tmp;
}

void build(int l, int r, int rt) {
    if (l == r) {
        if (s[l] == '(')
            ln[rt] = 1;
        else
            rn[rt] = 1;
        return ;
    }
    
    int mid = (l+r)>>1;
    build(lson);
    build(rson);
    PushUp(rt);
}

pii query(int l, int r, int rt) {
    if (L<=l && R>=r) {
        return mp(ln[rt], rn[rt]);
    }
    int mid = (l+r)>>1;
    if (mid < L) {
        return query(rson);
    } else if (mid >= R) {
        return query(lson);
    } else {
        pii p1 = query(lson);
        pii p2 = query(rson);
        pii ret;
        int tmp = min(p1.fir, p2.sec);
        ret.fir = p1.fir + p2.fir - tmp;
        ret.sec = p1.sec + p2.sec - tmp;
        return ret;
    }
}

int main() {
    ios::sync_with_stdio(false);
    #ifndef ONLINE_JUDGE
        freopen("data.in", "r", stdin);
        freopen("data.out", "w", stdout);
    #endif
    
    scanf("%s", s+1);
    
    int n = strlen(s+1), m;
    pii p;
    int ans;
    
    build(1, n, 1);
    scanf("%d", &m);
    while (m--) {
        scanf("%d %d", &L, &R);
        p = query(1, n, 1);
        ans = R-L+1-p.fir-p.sec;
        printf("%d
", ans);
    }
    
    #ifndef ONLINE_JUDGE
        printf("time = %d.
", (int)clock());
    #endif
    
    return 0;
}