UVA116

来源：互联网发布：淘宝洗车工具大全编辑：程序博客网时间：2024/06/10 14:25
很大的一个错误。正向推只能保证前者最小，逆向才能保证字典序最小。附上WA的代码
#include <bits/stdc++.h>using namespace std;const int N = 12, M = 102;int e[N][M], n, m;int dp[N][M], pre[N][M];void ptr(){     for(int i = 1;i <= n;i ++) {        for(int j = 1;j <= m;j ++) {            printf("%3d ",dp[i][j]);        } printf("\n");    }}int main(){    freopen("e:\\j1.txt","r",stdin);    freopen("e:\\j2.txt","w",stdout);    while(scanf("%d%d",&n,&m) != EOF) {        memset(dp, 0x3f, sizeof(dp));        for(int i = 1;i <= n;i ++) {            for(int j = 1;j <= m;j ++) {                scanf("%d",&e[i][j]);            }        }        for(int j = 1;j <= m;j ++) {            for(int i = 1;i <= n;i ++) {                if(j == 1) {                    dp[i][j] = e[i][j];                } else {                    dp[i][j] = dp[i][j - 1] + e[i][j];                    pre[i][j] = i;                    if(i == 1) {                        if(dp[i][j] > dp[i + 1][j - 1] + e[i][j]) {                            dp[i][j] = dp[i + 1][j - 1] + e[i][j];                            pre[i][j] = 2;                        }                        if(dp[i][j] > dp[n][j - 1] + e[i][j]) {                            dp[i][j] = dp[n][j - 1] + e[i][j];                            pre[i][j] = n;                        }                    } else if(i == n) {                        int ok  = 0;                        if(dp[i][j] >= dp[1][j - 1] + e[i][j]) {                            dp[i][j] = dp[1][j - 1] + e[i][j];                            pre[i][j] = 1;  ok = 1;                        }                        if( (ok && dp[i][j] > dp[i - 1][j - 1] + e[i][j]) || (!ok && dp[i][j] >= dp[i - 1][j - 1] + e[i][j]) ) {                            dp[i][j] = dp[i - 1][j - 1] + e[i][j];                            pre[i][j] = n - 1;                        }                    }  else {                        if(dp[i][j] >= dp[i - 1][j - 1] + e[i][j]) {                            dp[i][j] = dp[i - 1][j - 1] + e[i][j];                            pre[i][j] = i - 1;                        }                        if(dp[i][j] > dp[i + 1][j - 1] + e[i][j]) {                            dp[i][j] = dp[i + 1][j - 1] + e[i][j];                            pre[i][j] = i + 1;                        }                    }                }            }        }        //ptr();        int now, ans = 0x3f3f3f3f;        for(int i = 1;i <= n;i ++) {            if(ans > dp[i][m]) {                ans = dp[i][m];            }        }        vector<int>p;        for(int i = 1;i <= n;i ++) {            if(dp[i][m] == ans)  p.push_back(i);        }        string t;        for(int i = 0;i < p.size();i ++) {            string s;            s += p[i] + '0';            int now = p[i];            for(int k = m;k >= 2;k --) {                s += pre[now][k] + '0'; now = pre[now][k];            }            reverse(begin(s), end(s));            if(i == 0) t = s;            else t = min(t, s);        }        for(int i = 0;i < m;i ++) {            if(t[i] == ':') {                if(i == m - 1) printf("10");                else printf("10 ");            } else {                if(i == m - 1) printf("%c",t[i]);                else printf("%c ",t[i]);            }        }        printf("\n%d\n", ans);    }    return 0;}
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