[HIHO1299]打折机票（线段树）

题目链接：http://hihocoder.com/problemset/problem/1299

线段树，按照t为下标去更新v，更新的时候要保留最大的那个。

 #include <algorithm>
 #include <iostream>
 #include <iomanip>
 #include <cstring>
 #include <climits>
 #include <complex>
 #include <fstream>
 #include <cassert>
 #include <cstdio>
 #include <bitset>
 #include <vector>
 #include <deque>
 #include <queue>
 #include <stack>
 #include <ctime>
 #include <set>
 #include <map>
 #include <cmath>

 using namespace std;

 //kirai²»ÊÇɳ²è£¬²»»áÍü¼ÇÐÞ¸Ämaxn
 #define lson l, m, rt << 1
 #define rson m + 1, r, rt << 1 | 1
 typedef long long ll;
 typedef struct Node {
     int t, v;
 }Node;
 const int maxn = ;
 int n, m;
 int sum[maxn<<];

 void pushUP(int rt) {
     //modify
     sum[rt] = max(sum[rt<<], sum[rt<<|]);
 }

 void build(int l, int r, int rt) {
     if(l == r) {
         sum[rt] = -;
         return;
     }
     int m = (l + r) >> ;
     build(lson);
     build(rson);
     pushUP(rt);
 }

 void update(int p, int add, int l, int r, int rt) {
     if(l == r) {
         sum[rt] = max(sum[rt], add);
         return;
     }
     int m = (l + r) >> ;
     if(p <= m) {
         update(p, add, lson);
     }
     else {
         update(p, add, rson);
     }
     pushUP(rt);
 }

 int query(int L, int R, int l, int r, int rt) {
     if(L <= l && r <= R) {
         return sum[rt];
     }
     int m = (l + r) >> ;
     int ret = ;
     if(L <= m) {
         //modify
         ret = max(ret, query(L, R, lson));
     }
     if(R > m) {
         //modify
         ret = max(ret, query(L, R, rson));
     }
     return ret;
 }

 int main() {
     // freopen("in", "r", stdin);
     while(~scanf("%d%d", &n, &m)) {
         int t, v;
         build(, n, );
         for(int i = ; i < n; i++) {
             scanf("%d%d", &t, &v);
             update(t, v, , n, );
         }
         int a, b;
         while(m--) {
             scanf("%d%d", &a, &b);
             int ans = query(a, b, , n, );
             if(ans <= ) printf("None\n");
             else printf("%d\n", ans);
         }
     }
     return ;
 }

 #include <bits/stdc++.h>
 using namespace std;

 #define lrt rt << 1
 #define rrt rt << 1 | 1
 const int maxn = ;
 typedef struct Node {
     int l, r;
     int sum;
 }Node;
 Node T[maxn<<];
 int n, m;

 void pushUP(int rt) {
     T[rt].sum = max(T[lrt].sum, T[rrt].sum);
 }

 void build(int rt, int l, int r) {
     T[rt].l = l;
     T[rt].r = r;
     T[rt].sum = -;
     if(l == r) return;
     int mid = (l + r) >> ;
     build(lrt, l, mid);
     build(rrt, mid+, r);
     pushUP(rt);
 }

 void update(int rt, int pos, int val) {
     if(T[rt].l > pos || T[rt].r < pos) return;
     if(T[rt].l <= pos && T[rt].r >= pos) T[rt].sum = max(T[rt].sum, val);
     if(T[rt].l == T[rt].r) return;
     update(lrt, pos, val);
     update(rrt, pos, val);
     pushUP(rt);
 }

 int query(int rt, int l, int r) {
     int ret = -;
     if(T[rt].l > r || T[rt].r < l) return ret;
     if(T[rt].l >= l && T[rt].r <= r) return T[rt].sum;
     if(T[rt].l == T[rt].r) return ret;
     ret = max(ret, query(lrt, l, r));
     ret = max(ret, query(rrt, l, r));
     return ret;
 }

 int main() {
     // freopen("in", "r", stdin);
     int a, b;
     while(~scanf("%d%d",&n,&m)) {
         build(, , n);
         for(int i = ; i <= n; i++) {
             scanf("%d %d", &a, &b);
             update(, a, b);
         }
         while(m--) {
             scanf("%d %d", &a, &b);
             int ret = query(, a, b);
             if(ret == -) puts("None");
             else printf("%d\n", ret);
         }
     }
     return ;
 }