【数据结构】[luoguP1440]求m区间内的最小值

题目

线段树做了一遍 t了三个点可能是我太弱
代码如下

#include
#include
#include

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
#include
#include

    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 
        ll h = 1,t = 0;
        for(int i=1;iwhile(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

转载于:https://www.cnblogs.com/ars4me/p/7536177.html