| 记录编号 |
561108 |
评测结果 |
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAA |
| 题目名称 |
3537.[POJ 2104]第k小的数 |
最终得分 |
100 |
| 用户昵称 |
yrtiop |
是否通过 |
通过 |
| 代码语言 |
C++ |
运行时间 |
0.818 s |
| 提交时间 |
2021-06-21 19:01:53 |
内存使用 |
6.54 MiB |
显示代码纯文本
//整体分治
#include <cstdio>
#include <algorithm>
#include <cstring>
using namespace std;
const int maxn = 100005;
struct rec {
int l,r,k;
int op;
rec() {
l = r = k = 0;
op = 0;
}
}q[maxn << 1],lq[maxn << 1],rq[maxn << 1];
const int INF = 1e9;
int n,m,t;
int a[maxn],c[maxn];
int ans[maxn];
int lowbit(int x) {
return x & -x;
}
void update(int x,int val) {
for(int i = x;i <= n;i += lowbit(i)) {
c[i] += val;
}
return ;
}
int ask(int x) {
int ans = 0;
for(;x;x -= lowbit(x)) {
ans += c[x];
}
return ans;
}
void solve(int l,int r,int st,int ed) {
if(st > ed)return ;
if(l == r) {
for(int i = st;i <= ed;++ i) {
if(q[i].op) {
ans[q[i].op] = l;
}
}
return ;
}
int mid = l + r >> 1;
int lt = 0,rt = 0;
for(int i = st;i <= ed;++ i) {
if(!q[i].op) {
if(q[i].k <= mid)update(q[i].l , 1),lq[++ lt] = q[i];
else rq[++ rt] = q[i];
}
else {
int cnt = ask(q[i].r) - ask(q[i].l - 1);
if(cnt >= q[i].k)lq[++ lt] = q[i];
else q[i].k -= cnt,rq[++ rt] = q[i];
}
}
for(int i = ed;i >= st;-- i) {
if(!q[i].op&&q[i].k <= mid)update(q[i].l , - 1);
}
for(int i = 1;i <= lt;++ i)q[st + i - 1] = lq[i];
for(int i = 1;i <= rt;++ i)q[st + lt + i - 1] = rq[i];
solve(l , mid , st , st + lt - 1);
solve(mid + 1 , r , st + lt , ed);
return ;
}
int main() {
freopen("knumber.in","r",stdin);
freopen("knumber.out","w",stdout);
scanf("%d%d",&n,&m);
for(int i = 1;i <= n;++ i) {
scanf("%d",&a[i]);
q[++ t].op = 0;
q[t].l = i;
q[t].k = a[i];
}
for(int i = 1;i <= m;++ i) {
++ t;
q[t].op = i;
scanf("%d%d%d",&q[t].l,&q[t].r,&q[t].k);
}
solve(-INF , INF , 1 , t);
for(int i = 1;i <= m;++ i) {
printf("%d\n",ans[i]);
}
fclose(stdin);
fclose(stdout);
return 0;
}