URAL 1029 Ministry

URAL_1029

    dp。

#include<stdio.h>

#include<string.h>

#define MAXN 110

#define MAXM 510

int N, M, a[MAXN][MAXM], p[MAXN][MAXM];

long long f[MAXN][MAXM];

void init()

{

    int i, j;

    for(i = 1; i <= N; i ++)

        for(j = 1; j <= M; j ++)

            scanf("%d", &a[i][j]);

}

void dfs(int x, int y)

{

    if(p[x][y] == -1)

    {

        printf("%d", y);

        return ;

    }

    if(p[x][y] == 0)

        dfs(x - 1, y);

    else if(p[x][y] == 1)

        dfs(x, y - 1);

    else

        dfs(x, y + 1);

    printf(" %d", y);

}

void solve()

{

    int i, j, x, y;

    long long ans;

    for(i = 1; i <= M; i ++)

        f[1][i] = a[1][i], p[1][i] = -1;

    for(i = 2; i <= N; i ++)

    {

        for(j = 1; j <= M; j ++)

            f[i][j] = f[i - 1][j] + a[i][j], p[i][j] = 0;

        for(j = 2; j <= M; j ++)

            if(f[i][j - 1] + a[i][j] < f[i][j])

                f[i][j] = f[i][j - 1] + a[i][j], p[i][j] = 1;

        for(j = M - 1; j >= 1; j --)

            if(f[i][j + 1] + a[i][j] < f[i][j])

                f[i][j] = f[i][j + 1] + a[i][j], p[i][j] = 2;

    }

    ans = f[N][1], x = N, y = 1;

    for(i = 2; i <= M; i ++)

        if(f[N][i] < ans)

            ans = f[N][i], y = i;

    dfs(x, y);

    printf("\n");

}

int main()

{

    while(scanf("%d%d", &N, &M) == 2)

    {

        init();

        solve();

    }

    return 0;

}