HDU 2795 Billboard （线段树，单点查询）

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HDU 2795

一个h*w的公告牌，要在其上贴公告，尽量往上，同一高度尽量靠左。求第n个广告所在的行数。没有合适的位置贴了则输出-1。

参考博客：http://blog.csdn.net/qiqi_skystar/article/details/50299743

#include <iostream>#include <cstdio>#include <cstring>#include <algorithm>using namespace std;struct node {int l, r, m;int val;};int h, w, n;node T[200100 << 2];void build(int rt, int l, int r) {T[rt].val = w;T[rt].l = l;T[rt].r = r;T[rt].m = (l + r) >> 1;if(l == r) return;build(rt << 1, l, T[rt].m);build(rt << 1 | 1, T[rt].m + 1, r);}void query(int rt, int x) {if(T[rt].l == T[rt].r) {printf("%d\n", T[rt].l);T[rt].val -= x;return;}if(x <= T[rt << 1].val) {query(rt << 1, x);}else {query(rt << 1 | 1, x);}T[rt].val = max(T[rt << 1].val, T[rt << 1 | 1].val);}int main() {    while(~scanf("%d %d %d", &h, &w, &n)) {    if(h > n) h = n;    build(1, 1, h);    while(n--) {    int x;    scanf("%d", &x);    if(x > T[1].val) {    printf("-1\n");}else {query(1, x);}}}    return 0;}

#include <bits/stdc++.h>using namespace std;struct node{int l, r, m;int val;};const int maxn = 200100;int h, w, n, ans;node T[maxn << 2];int a[maxn];void pushup(int rt)  {T[rt].val = max(T[rt << 1].val, T[rt << 1 | 1].val);}void build(int begin, int end, int rt) {T[rt].l = begin;T[rt].r = end;T[rt].m = (T[rt].l + T[rt].r) >> 1;if(begin == end) {T[rt].val = w;return ;}build(T[rt].l, T[rt].m, rt << 1);build(T[rt].m + 1, T[rt].r, rt << 1 | 1);pushup(rt);}void update(int add, int rt) {if(T[rt].l == T[rt].r) {T[rt].val -= add;printf("%d\n", T[rt].l);return ;}if(add <= T[rt << 1].val) update(add, rt << 1);else update(add, rt << 1 | 1);pushup(rt);}int main() {while(~scanf("%d %d %d", &h, &w, &n)) {if(h > n) h = n;  //解题关键 build(1, h, 1);int l;for(int i = 0; i < n; i++) {scanf("%d", &l);if(T[1].val < l) {puts("-1");continue;}update(l, 1);}}return 0;}

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