poj2823 Sliding Window(单调队列)

模版题,就是维护一个合法区间的最值。C++写的莫名的TLE了, 换成C就过了。

#include <stdio.h>
#define maxn  1010000
struct Element {
    int pos, val;
}maxque[maxn], minque[maxn];
int maxhead,maxtail;
int minhead,mintail;
int n, k;
int A[maxn],B[maxn];
int main()
{    
    // freopen("in.txt","r",stdin);
    // freopen("out.txt","w",stdout);
    int i, cur, val;
    while(~scanf("%d%d",&n,&k) ) {
        maxhead = maxtail = 0;
        minhead = mintail = 0;
        cur = 0;
        for (i = 0;i < k;++i) {
            scanf("%d",&val);
            while(maxhead < maxtail && maxque[maxtail - 1].val <= val) maxtail--;
            maxque[maxtail].val = val;
            maxque[maxtail].pos = i;
            maxtail++;

            while(minhead < mintail && minque[mintail - 1].val >= val) mintail--;
            minque[mintail].val = val;
            minque[mintail].pos = i;
            mintail++;
        }
        for (i = k;i < n;++i) {
            A[cur] = maxque[maxhead].val;
            B[cur] = minque[minhead].val;
            cur++;
            scanf("%d",&val);

            while(maxhead < maxtail && i - maxque[maxhead].pos >= k) maxhead++;
            while(maxhead < maxtail && maxque[maxtail - 1].val <= val) maxtail--;
            maxque[maxtail].val = val;
            maxque[maxtail].pos = i;
            maxtail++;
            while(minhead < mintail && i - minque[minhead].pos >= k) minhead++;
            while(minhead < mintail && minque[mintail - 1].val >= val) mintail--;
            minque[mintail].val = val;
            minque[mintail].pos = i;
            mintail++;
        }
        A[cur] = maxque[maxhead].val;
        B[cur] = minque[minhead].val;
        cur++;
        for (i = 0;i < cur;++i)
            printf("%d%c", B[i], i == cur - 1?'\n':' ');
        for (i = 0;i < cur;++i)
            printf("%d%c", A[i], i == cur - 1?'\n':' ');
    }
    return 0;
}

#include <stdio.h>
#define lson(x) ((x) << 1)
#define rson(x) ((x) << 1 | 1)
#define inf 1 << 30
#define INF 0x3f3f3f3f
#define maxn 1000010
int a[maxn];
struct Node {
    int Min, Max;
    int l, r;
}p[maxn*4];
int mid;
int max(int x,int y) {
    return x > y?x:y;
}
int min(int x,int y) {
    return x < y?x:y;
}
void up(int rt) {
    p[rt].Max = max(p[lson(rt)].Max, p[rson(rt)].Max);
    p[rt].Min = min(p[lson(rt)].Min, p[rson(rt)].Min);
}
void build(int rt,int L,int R) {
    p[rt].l = L, p[rt].r = R;
    if (L == R) {
        p[rt].Min = p[rt].Max = a[L];
        return ;
    }
    //mid = (L + R) >> 1;
    p[rt].Min = INF;
    p[rt].Max = 0;
    build(lson(rt), L, (L+R) >> 1);
    build(rson(rt), ((L + R) >> 1) + 1, R);
    up(rt);
}
int Max, Min;
void QueryMax(int rt,int L,int R) {
    if (L <= p[rt].l && p[rt].r <= R) {
        Max = max(Max, p[rt].Max);
        return ;
    }
   // mid = (p[rt].l + p[rt].r) >> 1;
    if (L <= (p[rt].l + p[rt].r) >> 1) QueryMax(lson(rt), L, R);
    if (R > (p[rt].l + p[rt].r) >> 1) QueryMax(rson(rt), L, R);
}
void QueryMin(int rt,int L,int R) {
    if (L <= p[rt].l && p[rt].r <= R) {
        Min = min(Min, p[rt].Min);
        return ;
    }
    //mid = (p[rt].l + p[rt].r) >> 1;
    if (L <= (p[rt].l + p[rt].r) >> 1) QueryMin(lson(rt),L,R);
    if (R > (p[rt].l + p[rt].r) >> 1) QueryMin(rson(rt),L,R);
}
int main()
{
    // freopen("in.txt","r",stdin);
    int n, k, i;
    while(scanf("%d%d",&n,&k) == 2) {
        for (i = 1;i <= n;++i)
            scanf("%d",&a[i]);
        build(1, 1, n);
        for (i = k;i <= n;++i) {
            Min = inf;
            QueryMin(1,i - k + 1,i);
            printf("%d%c",Min,i==n?'\n':' ');
        }
        for (i = k;i <= n;++i) {
            Max = -inf;
            QueryMax(1, i - k + 1,i);
            printf("%d%c", Max,i == n?'\n':' ');
        }
    }
    return 0;
}


你可能感兴趣的:(单调队列)