水线段树。
1 /* 380C */ 2 #include <iostream> 3 #include <string> 4 #include <map> 5 #include <queue> 6 #include <set> 7 #include <stack> 8 #include <vector> 9 #include <deque> 10 #include <algorithm> 11 #include <cstdio> 12 #include <cmath> 13 #include <ctime> 14 #include <cstring> 15 #include <climits> 16 #include <cctype> 17 #include <cassert> 18 #include <functional> 19 #include <iterator> 20 #include <iomanip> 21 using namespace std; 22 //#pragma comment(linker,"/STACK:102400000,1024000") 23 24 #define sti set<int> 25 #define stpii set<pair<int, int> > 26 #define mpii map<int,int> 27 #define vi vector<int> 28 #define pii pair<int,int> 29 #define vpii vector<pair<int,int> > 30 #define rep(i, a, n) for (int i=a;i<n;++i) 31 #define per(i, a, n) for (int i=n-1;i>=a;--i) 32 #define clr clear 33 #define pb push_back 34 #define mp make_pair 35 #define fir first 36 #define sec second 37 #define all(x) (x).begin(),(x).end() 38 #define SZ(x) ((int)(x).size()) 39 #define lson l, mid, rt<<1 40 #define rson mid+1, r, rt<<1|1 41 42 const int maxn = 1e6+5; 43 char s[maxn]; 44 int ln[maxn<<2]; 45 int rn[maxn<<2]; 46 int L, R; 47 48 inline void PushUp(int rt) { 49 int lb = rt<<1; 50 int rb = (rt<<1)|1; 51 int tmp = min(ln[lb], rn[rb]); 52 53 ln[rt] = ln[lb] + ln[rb] - tmp; 54 rn[rt] = rn[lb] + rn[rb] - tmp; 55 } 56 57 void build(int l, int r, int rt) { 58 if (l == r) { 59 if (s[l] == '(') 60 ln[rt] = 1; 61 else 62 rn[rt] = 1; 63 return ; 64 } 65 66 int mid = (l+r)>>1; 67 build(lson); 68 build(rson); 69 PushUp(rt); 70 } 71 72 pii query(int l, int r, int rt) { 73 if (L<=l && R>=r) { 74 return mp(ln[rt], rn[rt]); 75 } 76 int mid = (l+r)>>1; 77 if (mid < L) { 78 return query(rson); 79 } else if (mid >= R) { 80 return query(lson); 81 } else { 82 pii p1 = query(lson); 83 pii p2 = query(rson); 84 pii ret; 85 int tmp = min(p1.fir, p2.sec); 86 ret.fir = p1.fir + p2.fir - tmp; 87 ret.sec = p1.sec + p2.sec - tmp; 88 return ret; 89 } 90 } 91 92 int main() { 93 ios::sync_with_stdio(false); 94 #ifndef ONLINE_JUDGE 95 freopen("data.in", "r", stdin); 96 freopen("data.out", "w", stdout); 97 #endif 98 99 scanf("%s", s+1); 100 101 int n = strlen(s+1), m; 102 pii p; 103 int ans; 104 105 build(1, n, 1); 106 scanf("%d", &m); 107 while (m--) { 108 scanf("%d %d", &L, &R); 109 p = query(1, n, 1); 110 ans = R-L+1-p.fir-p.sec; 111 printf("%d ", ans); 112 } 113 114 #ifndef ONLINE_JUDGE 115 printf("time = %d. ", (int)clock()); 116 #endif 117 118 return 0; 119 }