Added 1 solution & modified 2 solutions

varunu28 · varunu28 · commit 5a74e2046471 · 2020-08-01T12:25:55.000-05:00
diff --git a/Easy/Bulls and Cows.java b/Easy/Bulls and Cows.java
@@ -0,0 +1,25 @@
+class Solution {
+  public String getHint(String secret, String guess) {
+    int[] counter = new int[10];
+    int cows = 0;
+    int bulls = 0;
+    for (int i = 0; i < guess.length(); i++) {
+      int s = Character.getNumericValue(secret.charAt(i));
+      int g = Character.getNumericValue(guess.charAt(i));
+      if (s == g) {
+        bulls++;
+      }
+      else {
+        if (counter[s] < 0) {
+          cows++;
+        }
+        if (counter[g] > 0) {
+          cows++;
+        }
+        counter[s]++;
+        counter[g]--;
+      }
+    }
+    return new StringBuilder().append(bulls).append("A").append(cows).append("B").toString();
+  }
+}
diff --git a/Easy/Detect Capital.java b/Easy/Detect Capital.java
@@ -1,25 +1,22 @@
 class Solution {
   public boolean detectCapitalUse(String word) {
     int n = word.length();
-    boolean capitalFirst = Character.isUpperCase(word.charAt(0));
-    int idx = 1;
-    if (idx < n) {
-      boolean capitalSecond = Character.isUpperCase(word.charAt(idx));
-      for (idx = 1; idx < n; idx++) {
-        if (capitalFirst && capitalSecond) {
-          if (Character.isLowerCase(word.charAt(idx))) {
-            return false;
-          }
+    if (n == 0) {
+      return true;
+    }
+    boolean firstCaps = Character.isUpperCase(word.charAt(0));
+    for (int i = 1; i < n; i++) {
+      if (firstCaps) {
+        if (Character.isUpperCase(word.charAt(1)) && !Character.isUpperCase(word.charAt(i))) {
+          return false;
         }
-        else if (capitalFirst && !capitalSecond) {
-          if (Character.isUpperCase(word.charAt(idx))) {
-            return false;
-          }
+        if (!Character.isUpperCase(word.charAt(1)) && Character.isUpperCase(word.charAt(i))) {
+          return false;
         }
-        else {
-          if (Character.isUpperCase(word.charAt(idx))) {
-            return false;
-          }
+      }
+      else {
+        if (Character.isUpperCase(word.charAt(i))) {
+          return false;
         }
       }
     }
diff --git a/Medium/Bulls and Cows.java b/Medium/Bulls and Cows.java
diff --git a/Medium/Knight Probability in Chessboard.java b/Medium/Knight Probability in Chessboard.java
@@ -0,0 +1,30 @@
+class Solution {
+  public double knightProbability(int N, int K, int r, int c) {
+    double[][] dp = new double[N][N];
+    int[] rowMoves = new int[]{2, 2, 1, 1, -1, -1, -2, -2};
+    int[] colMoves = new int[]{1, -1, 2, -2, 2, -2, 1, -1};
+    dp[r][c] = 1;
+    while (K-- >  0) {
+      double[][] copy = new double[N][N];
+      for (int i = 0; i < N; i++) {
+        for (int j = 0; j < N; j++) {
+          for (int k = 0; k < 8; k++) {
+            int destR = i + rowMoves[k];
+            int destC = j + colMoves[k];
+            if (destR >= 0 && destR < N && destC >= 0 && destC < N) {
+              copy[destR][destC] += dp[i][j] / 8.0;
+            }
+          }
+        }
+      }
+      dp = copy;
+    }
+    double ans = 0.0;
+    for (double[] row : dp) {
+      for (double val : row) {
+        ans += val;
+      }
+    }
+    return ans;
+  }
+}
