[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 = 100010;
int n, m;
int sum[maxn<<2];

void pushUP(int rt) {
    //modify
    sum[rt] = max(sum[rt<<1], sum[rt<<1|1]);
}

void build(int l, int r, int rt) {
    if(l == r) {
        sum[rt] = -1;
        return;
    }
    int m = (l + r) >> 1;
    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) >> 1;
    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) >> 1;
    int ret = 0;
    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(1, n, 1);
        for(int i = 0; i < n; i++) {
            scanf("%d%d", &t, &v);
            update(t, v, 1, n, 1);
        }
        int a, b;
        while(m--) {
            scanf("%d%d", &a, &b);
            int ans = query(a, b, 1, n, 1);
            if(ans <= 0) printf("None
");
            else printf("%d
", ans);
        }
    }
    return 0;
}

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

#define lrt rt << 1
#define rrt rt << 1 | 1
const int maxn = 100100;
typedef struct Node {
    int l, r;
    int sum;
}Node;
Node T[maxn<<2];
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 = -1;
    if(l == r) return;
    int mid = (l + r) >> 1;
    build(lrt, l, mid);
    build(rrt, mid+1, 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 = -1;
    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(1, 1, n);
        for(int i = 1; i <= n; i++) {
            scanf("%d %d", &a, &b);
            update(1, a, b);
        }
        while(m--) {
            scanf("%d %d", &a, &b);
            int ret = query(1, a, b);
            if(ret == -1) puts("None");
            else printf("%d
", ret);
        }
    }
    return 0;
}