Update Solution.java

Author: yanglbme

solution/2300-2399/2338.Count the Number of Ideal Arrays/Solution.java

@@ -1,41 +1,30 @@
 class Solution {
-    private int[][] f;
-    private int[][] c;
-    private int n;
-    private int m;
-    private static final int MOD = (int) 1e9 + 7;
-
     public int idealArrays(int n, int maxValue) {
-        this.n = n;
-        this.m = maxValue;
-        this.f = new int[maxValue + 1][16];
-        for (int[] row : f) {
-            Arrays.fill(row, -1);
-        }
-        c = new int[n][16];
+        final int mod = (int) 1e9 + 7;
+        int[][] c = new int[n][16];
         for (int i = 0; i < n; ++i) {
             for (int j = 0; j <= i && j < 16; ++j) {
-                c[i][j] = j == 0 ? 1 : (c[i - 1][j] + c[i - 1][j - 1]) % MOD;
+                c[i][j] = j == 0 ? 1 : (c[i - 1][j] + c[i - 1][j - 1]) % mod;
             }
         }
-        int ans = 0;
-        for (int i = 1; i <= m; ++i) {
-            ans = (ans + dfs(i, 1)) % MOD;
+        long[][] f = new long[maxValue + 1][16];
+        for (int i = 1; i <= maxValue; ++i) {
+            f[i][1] = 1;
         }
-        return ans;
-    }
-
-    private int dfs(int i, int cnt) {
-        if (f[i][cnt] != -1) {
-            return f[i][cnt];
+        for (int j = 1; j < 15; ++j) {
+            for (int i = 1; i <= maxValue; ++i) {
+                int k = 2;
+                for (; k * i <= maxValue; ++k) {
+                    f[k * i][j + 1] = (f[k * i][j + 1] + f[i][j]) % mod;
+                }
+            }
         }
-        int res = c[n - 1][cnt - 1];
-        if (cnt < n) {
-            for (int k = 2; k * i <= m; ++k) {
-                res = (res + dfs(k * i, cnt + 1)) % MOD;
+        long ans = 0;
+        for (int i = 1; i <= maxValue; ++i) {
+            for (int j = 1; j < 16; ++j) {
+                ans = (ans + f[i][j] * c[n - 1][j - 1]) % mod;
             }
         }
-        f[i][cnt] = res;
-        return res;
+        return (int) ans;
     }
-}
+}