【DP】 HDOJ 2829 Lawrence

#include <iostream>
#include <queue> 
#include <stack> 
#include <map> 
#include <set> 
#include <bitset> 
#include <cstdio> 
#include <algorithm> 
#include <cstring> 
#include <climits>
#include <cstdlib>
#include <cmath>
#include <time.h>
#define maxn 1005
#define maxm 1000005
#define eps 1e-10
#define mod 1000000007
#define INF 0x3f3f3f3f
#define PI (acos(-1.0))
#define lowbit(x) (x&(-x))
#define mp make_pair
#define ls o<<1
#define rs o<<1 | 1
#define lson o<<1, L, mid 
#define rson o<<1 | 1, mid+1, R
#pragma comment(linker, "/STACK:16777216")
typedef long long LL;
typedef unsigned long long ULL;
//typedef int LL;
using namespace std;
LL qpow(LL a, LL b){LL res=1,base=a;while(b){if(b%2)res=res*base;base=base*base;b/=2;}return res;}
LL powmod(LL a, LL b){LL res=1,base=a;while(b){if(b%2)res=res*base%mod;base=base*base%mod;b/=2;}return res;}
void scanf(int &__x){__x=0;char __ch=getchar();while(__ch==' '||__ch=='
')__ch=getchar();while(__ch>='0'&&__ch<='9')__x=__x*10+__ch-'0',__ch = getchar();}
LL gcd(LL _a, LL _b){if(!_b) return _a;else return gcd(_b, _a%_b);}
// head

int dp[maxn][maxn];
int w[maxn][maxn];
int s[maxn][maxn];
int a[maxn];
int n, m;

void read(void)
{
	for(int i = 1; i <= n; i++) scanf("%d", &a[i]);
}

void debug(void)
{
	for(int i = 1; i<= m; i++) {
		for(int j = 1; j <= n; j++)
			printf("%lld ", dp[i][j]);
		printf("
");
	}
}

void work(void)
{
	for(int i = 1; i <= n; i++) {
		int t1 = 0, t2 = 0;
		for(int j = i; j <= n; j++) {
			t2 += t1 * a[j];
			t1 += a[j];
			w[i][j] = t2;
		}
	}
	for(int i = 1; i <= n; i++) dp[0][i] = w[1][i];
	for(int i = 1; i <= m; i++) s[i][n+1] = n;
	for(int i = 1; i <= m; i++)
		for(int j = n; j >= 1; j--) {
			dp[i][j] = INF;
			for(int k = s[i-1][j]; k <= s[i][j+1]; k++)
				if(dp[i][j] > dp[i-1][k] + w[k+1][j]) {
					dp[i][j] = dp[i-1][k] + w[k+1][j];
					s[i][j] = k;
				}
		}
	printf("%d
", dp[m][n]);

}

int main(void)
{
	while(scanf("%d%d", &n, &m), n != 0 || m != 0) {
		read();
		work();
	}

	return 0;
}