爲什麼我的備忘錄數組被初始化爲0 java？

Question

memo array is reinitialized to 0

我不明白爲什麼我的備忘錄被設置爲0再次，即使我初始化爲-1，它保持了備忘錄重置爲0。下面的代碼一直稱這是自己的，但在堆棧的第一個層次，備忘錄被初始化爲0

import java.util.Arrays; 

public class RGBTree { 
    public static void main(String[] args) { 
     RGBTree rgb = new RGBTree(); 
     String[] G = 
       {"..B.BB...RB..","......R..B.G.", 
         "B.......BB...",".......R...G.", 
         "B....GRB..R..","B...G.RG.R...", 
         ".R..RR..B.RB.","...RBG...G...", 
         "..B...B......","RBB..R.G....R", 
         "B...R.R......",".G.G..B.....R",".........R.R."}; 
     System.out.println(rgb.exist(G)); 

    } 


    public String exist(String[] G) { 
     int[][][][] memo = new int[(1 << 13)][13][13][13]; 
     int n = G.length; 
     int k = (n - 1)/3; 
     for (int i = 0; i < 1 << 13; i++) { 
      for (int j = 0; j < 13; j++) { 
       for (int l = 0; l < 13; l++) { 
        for (int m = 0; m < 13; m++) { 
         memo[i][j][k][l] = -1; 
        } 
       } 
      } 
     } 


     return (f(n, 1, k, 0, 0, 0, G, memo)) ? "Exist" : "Does not"; 

    } 

    private boolean f(int v, int mask, int k, int r, int g, int b, String[] graph, int[][][][]memo) { 

     boolean res = false; 
     if (memo[mask][r][g][b] != -1) { 
      res = memo[mask][r][g][b] == 1 ? true : false; 
     } else { 
      if (r == k && g == k && b == k) { 
       res = true; 
      } 
      for (int i = 0; i < v; i++) { 
       if (((mask & (1 << i)) == 1)) { 
        for (int j = 0; j < v; j++) { 
         if ((mask & (1 << j)) == 0 && graph[i].charAt(j) != '.') { 
          int nr = r, ng = g, nb = b; 
          char c = graph[i].charAt(j); 
          switch (c) { 
           case 'R': 
            nr++; 
            break; 
           case 'G': 
            ng++; 
            break; 
           case 'B': 
            nb++; 
            break; 

          } 


          if (nr <= k && ng <= k && nb <= k) { 
           res |= f(v, mask | (1 << j), k, nr, ng, nb, graph, memo); 
          } 
         } 

        } 
       } 
      } 
      memo[mask][r][g][b] = res ? 1 : 2; 

     } 
     return res; 

    } 
} 

Answer 1

你的循環索引i，j，l和m，但你在初始化中使用i，j，k和l。由於k在循環中沒有更改，因此您沒有初始化memo中的每個元素。你可以這樣做，

int[][][][] memo = new int[(1 << 13)][13][13][13]; 
for (int i = 0; i < memo.length; i++) { 
    for (int j = 0; j < memo[i].length; j++) { 
     for (int l = 0; l < memo[i][j].length; l++) { 
      Arrays.fill(memo[i][j][l], -1); 
     } 
    } 
}