poj 2163 Easy Trading

#include <iostream>#include <cstdio>#include <cstdlib>#include <cstring>using namespace std;#define maxn 10005int a, b, n;double p[maxn], sum[maxn];int dblcmp(double a, double b){    if (a < b)        return -1;    return 1;}int main(){    scanf("%d%d%d", &a, &b, &n);    sum[0] = 0;    for (int i = 1; i <= n; i++)    {        scanf("%lf", &p[i]);        sum[i] = sum[i - 1] + p[i];    }    if (dblcmp((sum[b] - sum[0]) * a, (sum[b] - sum[b - a]) * b) < 0)        printf("BUY ON DAY %dn", b);    else        printf("SELL ON DAY %dn", b);    for (int i = b + 1; i <= n; i++)        if (dblcmp((sum[i] - sum[i - b]) * a, (sum[i] - sum[i - a]) * b) < 0     && dblcmp((sum[i - 1] - sum[i - b - 1]) * a, (sum[i - 1]  - sum[i - a - 1]) * b) > 0) printf("BUY ON DAY %dn", i);        else if (dblcmp((sum[i] - sum[i - b]) * a, (sum[i] - sum[i - a]) * b)     > 0 && dblcmp((sum[i - 1] - sum[i - b - 1]) * a, (sum[i - 1]     - sum[i - a - 1]) * b) < 0) printf("SELL ON DAY %dn", i);    return 0;}