【HDOJ】1540 Tunnel Warfare

还不错的一道线段树区间合并。挺巧妙的用法。

 /* 1540 */
 #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 = ;
 int ls[maxn<<], rs[maxn<<], ms[maxn<<];
 int S[maxn], top;

 void Build(int l, int r, int rt) {
     ls[rt] = rs[rt] = ms[rt] = r - l + ;
     if (l == r)
         return ;

     int mid = (l + r) >> ;
     Build(lson);
     Build(rson);
 }

 void PushUp(int l, int r, int rt) {
     int mid = (l + r) >>;
     int lb = rt<<;
     int rb = lb |;

     ls[rt] = ls[lb];
     rs[rt] = rs[rb];
     if (ls[lb] == mid-l+)
         ls[rt] += ls[rb];
     if (rs[rb] == r-mid)
         rs[rt] += rs[lb];

     ms[rt] = max(ms[lb], ms[rb]);
     ms[rt] = max(ms[rt], rs[lb]+ls[rb]);
 }

 void update(int x, int delta, int l, int r, int rt) {
     if (l == r) {
         ls[rt] = rs[rt] = ms[rt] = delta;
         return ;
     }

     int mid = (l + r) >> ;

     if (x <= mid) {
         update(x, delta, lson);
     } else {
         update(x, delta, rson);
     }

     PushUp(l, r, rt);
 }

 int Query(int x, int l, int r, int rt) {
     if (l==r || ms[rt]== || ms[rt]==r-l+)
         return ms[rt];

     int mid = (l + r) >> ;
     int lb = rt<<;
     int rb = lb |;

     if (x <= mid) {
         if (x >= mid-rs[lb]+) {
             return Query(x, lson) + Query(mid+, rson);
         } else {
             return Query(x, lson);
         }
     } else {
         if (x <= mid+ls[rb]) {
             return Query(mid, lson) + Query(x, rson);
         } else {
             return Query(x, rson);
         }
     }
 }

 int main() {
     ios::sync_with_stdio(false);
     #ifndef ONLINE_JUDGE
         freopen("data.in", "r", stdin);
         freopen("data.out", "w", stdout);
     #endif

     int n, m, x;
     char cmd[];
     int ans;

     while (scanf("%d %d", &n, &m)!=EOF) {
         Build(, n, );
         top = ;
         while (m--) {
             scanf("%s", cmd);
             if (cmd[] == 'D') {
                 scanf("%d", &x);
                 S[top++] = x;
                 update(x, , , n, );
             } else if (cmd[] == 'Q') {
                 scanf("%d", &x);
                 ans = Query(x, , n, );
                 printf("%d\n", ans);
             } else {
                 if (top > ) {
                     x = S[--top];
                     update(x, , , n, );
                 }
             }
         }
     }

     #ifndef ONLINE_JUDGE
         printf("time = %d.\n", (int)clock());
     #endif

     return ;
 }