Dynamic Planning--board

Wikioi 1010 River crossing StrokeTitle Description Description

, a point has a river stroke, need to go to target point B. Stroke rule: can be down, or to the right. At the same time on the board at any point there is a horse (such as the C point), the point where the horse is located and all jumps one step up to the point known as the other horse's control points. For example, a horse on a C point can control 9 points (the p1,p2 in the picture ...). P8 and C). The stroke cannot pass through the other horse's control point.

The chessboard coordinates, A point (0,0), B Point (N,m) (N,m is not more than 20 integer, and by the keyboard input), the same position coordinates of the horse is required (convention: C is not equal to a, and C is not equal to B). You are now asked to calculate the number of strokes from the point where a is able to reach point B.

1<=n,m<=15

Enter a description Input Description

Keyboard input
Coordinates of Point B (n,m) and coordinates of the opponent's horse (x, y) {no error}

Output description Output Description

Screen output
An integer (the number of bars in the path).

Sample input Sample Input

6 6 3 2

Sample output Sample Output

17

Data range and Tips Data Size & Hint

As described

Ideas:

DP, preprocess all reachable points first

Code:

1#include <iostream>2#include <cstdio>3#include <string>4#include <cstring>5#include <algorithm>6 7 using namespacestd;8 Const intMAXN = $;9 intN,M,X,Y,DP[MAXN][MAXN],VIS[MAXN][MAXN];Ten  One intMain () { ACin>>n>>m>>x>>y; -memset (Vis,0,sizeof(Vis)); -Memset (DP,0,sizeof(DP)); then++; -m++; -X + +; -y++; +Vis[x][y] = vis[x-1][y+2] = vis[x-2][y+1] = vis[x-2][y-1] = vis[x-1][y-2] = vis[x+1][y+2] = vis[x+2][y+1] = vis[x+2][y-1] = vis[x+1][y-2] = -1; -dp[1][1] =1; +      for(inti =1; I <= n;i++){ A          for(intj =1; J <= m;j++){ at             if(Vis[i][j]! =-1){ -DP[I][J] = max (dp[i][j],dp[i-1][J] + dp[i][j-1]); -             } -              -         } -     } incout<<Dp[n][m]; -     return 0; to}

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Dynamic Planning--board