ACM/ICPC 2012 天津 - HDU 4433 - DP(顺推)

#include<cstdio>
#include<cmath>
#include<cstring>
#include<algorithm>
using namespace std;
char s1[1010], s2[1010];
int a[1010], b[1010];
int dp[1010][10][10];
const int INF = 999999999;

int main()
{
while(scanf("%s %s", s1, s2) != EOF)
{
int i, j, k, x, y;
int n = strlen(s1);
for(i = 0; i < n; i++)
{
a[i+1] = s1[i] - '0';
b[i+1] = s2[i] - '0';
}
a[n+1] = a[n+2] = 0;
b[n+1] = b[n+2] = 0;

for(i = 0; i <= n; i++)
for(x = 0; x < 10; x++)
for(y = 0; y < 10; y++)
dp[i][x][y] = INF;

dp[0][a[1]][a[2]] = 0;
for(i = 1; i <= n; i++)
{
for(x = 0; x < 10; x++)
{
for(y = 0; y < 10; y++)
{
int down = (b[i] - x + 10) % 10;
for(j = 0; j <= down; j++)
for(k = 0; k <= j; k++)
dp[i][(y+j)%10][(a[i+2]+k)%10] = min(dp[i-1][x][y] + down,
dp[i][(y+j)%10][(a[i+2]+k)%10]);
int up = 10 - down;
for(j = 0; j <= up; j++)
for(k = 0; k <= j; k++)
dp[i][(y-j+10)%10][(a[i+2]-k+10)%10] = min(dp[i-1][x][y] + up,
dp[i][(y-j+10)%10][(a[i+2]-k+10)%10]);

}
}
}
printf("%d\n",dp
[0][0]);
}
}