soj1084 Ski Race

Background: Did not consider the elevation can also be 0 and negative, so has been wrong for a long time.

Idea: dfs+ Memory search + recursion.

Learning: Memory Search.

#include <iostream> #include <cstring>using namespace Std;int area[52][52],memory[52][52];int m,n,max_ Time,k;int judge (int i1,int j1,int I,int j) {if (area[i1][j1]<area[i][j]&&i1>0&&j1>0&    &AMP;I1&LT;=N&AMP;&AMP;J1&LT;=M) return 1; else return 0;}    void Dfs (int i,int j,int time) {bool Ok=false;        if (Memory[i][j]) {time+=memory[i][j];        K= ((k<time) time:k);        Max_time= ((max_time<time) time:max_time);    Return    } if (judge (i+1,j,i,j)) {DFS (i+1,j,time+1); ok=true;}    if (judge (i,j+1,i,j)) {DFS (i,j+1,time+1); ok=true;}    if (judge (i-1,j,i,j)) {DFS (i-1,j,time+1); ok=true;}    if (judge (i,j-1,i,j)) {DFS (i,j-1,time+1); ok=true;} if (!ok) k= ((k<time)? time:k);}        int main (void) {while (cin>>n>>m&&n&&m) {memset (area,0,sizeof (area));        memset (memory,0,sizeof (memory));        max_time=0;        int i,j;      for (i=1;i<=n;i++) for (j=1;j<=m;j++)          cin>>area[i][j];                for (i=1;i<=n;i++) for (j=1;j<=m;j++) {k=0;                DFS (i,j,0);            Memory[i][j]=k;    } cout<<max_time<<endl; } return 0;}

soj1084 Ski Race