【最长下降子序列】北大 poj 1952 BUY LOW, BUY LOWER

/* THE PROGRAM IS MADE BY PYY *//*----------------------------------------------------------------------------//    Copyright (c) 2012 panyanyany All rights reserved.    URL   : http://poj.org/problem?id=1952    Name  : 1952 BUY LOW, BUY LOWER    Date  : Tuesday, July 10, 2012    Time Stage : 2 hours    Result:0411693panyanyany1952Accepted224K172MSC++1970B2012-07-10 09:44:02Test Data :Review :参考：http://blog.acmj1991.com/?p=606//----------------------------------------------------------------------------*/#include <stdio.h>#include <stdlib.h>#include <string.h>#include <math.h>#include <vector>#include <algorithm>#include <iostream>#include <queue>#include <set>#include <string>using namespace std ;#define MEM(a, v)        memset (a, v, sizeof (a))    // a for address, v for value#define max(x, y)        ((x) > (y) ? (x) : (y))#define min(x, y)        ((x) < (y) ? (x) : (y))#define INF     (0x3f3f3f3f)#define MAXN(5005)#define L(x)((x)<<1)#define R(x)(((x)<<1)|1)#define M(x, y)(((x)+(y)) >> 1)#define DB    //int sum, a[MAXN], dp[MAXN], route[MAXN];int LIS(int a[], int n){int i, j;for (i = 0; i < n; ++i){dp[i] = 1;route[i] = 1;for (j = 0; j < i; ++j){if (a[j] > a[i]){if (dp[j] + 1 > dp[i]){route[i] = route[j];dp[i] = dp[j] + 1;}else if (dp[j] + 1 == dp[i]){route[i] += route[j];}}}// 去重，比如 5 2 3 2，当 i==3时，计算到第2个2，那么对于以后的数来// 说，第1个2的route就是多余的了。因为凡是比2小的数，比如1，显然跟第2个2// 比较更好，因为(dp[3] = 3) > (dp[1] = 2)。然后再普及到一般的情况:// 5 2 1 2, 此时两个2的route和dp都一样，所以第一个2多余.for (j = 0; j < i; ++j)if (a[i] == a[j])route[j] = 0;}j = 0;for (i = 0; i < n; ++i){if (dp[j] < dp[i])j = i;}for (i = 0; i < n; ++i)if (i != j && dp[j] == dp[i])route[j] += route[i];return j;}int main(){int i, j, n;while (scanf("%d", &n) != EOF){for (i = 0; i < n; ++i)scanf("%d", a+i);j = LIS(a, n);printf("%d ", dp[j]);printf("%d\n", route[j]);}return 0;}