【数据结构】[luoguP1440]求m区间内的最小值
线段树做了一遍 t了三个点可能是我太弱
代码如下
#include<iostream>
#include<cstdio>
#include<cctype>
using namespace std;
#define in = read()
typedef long long ll;
const ll size = 8000000 + 10000;
#define left (rt<<1)
#define right (rt<<1|1)
#define lson l,mid,left
#define rson mid+1,r,right
#define mid ((l + r)>>1)
ll n,m;
ll tree[size];
inline ll read(){
ll num = 0, f = 1; char ch = getchar();
while (!isdigit(ch)){
if(ch == '-') f = -1;
ch = getchar();
}
while (isdigit(ch)){
num = num*10 + ch - '0';
ch = getchar();
}
return num*f;
}
inline ll pushup(ll rt){ tree[rt]=min(tree[left],tree[right]);}
void buildtree(ll l ,ll r ,ll rt){
if (l == r){ tree[rt] in ; return;}
buildtree(lson); buildtree(rson); pushup(rt);
}
ll query(ll from ,ll to ,ll l ,ll r ,ll rt){
if(from <= l && to >= r) return tree[rt];
ll ans = 0x7fffffff;
if(from <= mid) ans = query(from ,to ,lson);
if(to > mid) ans = min(ans ,query(from ,to ,rson));
return ans;
}
int main(){
n in; m in;
buildtree(1,n,1);
printf("0\n");
ll t = 1;
for(;;){
printf("%lld\n",query(1 ,t ,1 ,n ,1));
t ++;
if(t == m) break;
}
ll leftpoint = 1, rightpoint = m;
for(int i=1;i<=n-m;i++){
printf("%lld\n",query(leftpoint ,rightpoint ,1 ,n ,1));
leftpoint ++; rightpoint ++;
}
}
//COYG
后来改单调队列 于是题目变成了滑动窗口
慢慢滑 进队。。出队 队首肯定最小
代码如下
#include<iostream>
#include<cstdio>
#include<cctype>
using namespace std;
#define in = read()
typedef long long ll;
const ll size = 2000000 + 100000;
ll n,m;
ll a[size];
ll q[size],p[size];
inline ll read(){
ll num = 0, f = 1; char ch = getchar();
while (!isdigit(ch)){
if(ch == '-') f = -1;
ch = getchar();
}
while (isdigit(ch)){
num = num*10 + ch - '0';
ch = getchar();
}
return num*f;
}
int main(){
n in; m in;
for(int i=1;i<=n;i++) a[i] in;
printf("0\n");
/* ll l = 1;
for(int i=1;i<m;i++){
ll ans = 0x7fffffff;
for(int j=1;j<=l;j++)
if(a[j] < ans)
ans = a[j];
printf("%d\n",ans);
l ++;
}
*/
ll h = 1,t = 0;
for(int i=1;i<n;i++){
while(h <= t && q[t] >= a[i])
t --;
q[++ t] = a[i]; p[t] = i;
while(p[h] <= i - m)
h ++;
printf("%d\n",q[h]);
}
}
//COYG