Create shortest-distance-to-target-color.py

Author: kamyu104

Python/shortest-distance-to-target-color.py

@@ -0,0 +1,56 @@
+# Time:  O(n)
+# Space: O(n)
+
+class Solution(object):
+    def shortestDistanceColor(self, colors, queries):
+        """
+        :type colors: List[int]
+        :type queries: List[List[int]]
+        :rtype: List[int]
+        """
+        dp = [[float("inf") for _ in xrange(len(colors))] for _ in xrange(3)]
+        dp[colors[0]-1][0] = 0
+        for i in xrange(1, len(colors)):
+            for color in xrange(3):
+                dp[color][i] = dp[color][i-1]+1
+            dp[colors[i]-1][i] = 0
+
+        dp[colors[len(colors)-1]-1][len(colors)-1] = 0
+        for i in reversed(xrange(len(colors)-1)):
+            for color in xrange(3):
+                if abs(dp[color][i+1]-1) < dp[color][i]:
+                    dp[color][i] = dp[color][i+1]-1
+            dp[colors[i]-1][i] = 0
+         
+        return [abs(dp[color-1][i]) if abs(dp[color-1][i]) != float("inf") else -1 \
+                    for i, color in queries]
+
+# Time:  O(n)
+# Space: O(n)
+class Solution2(object):
+    def shortestDistanceColor(self, colors, queries):
+        """
+        :type colors: List[int]
+        :type queries: List[List[int]]
+        :rtype: List[int]
+        """
+        
+        left = [[float("inf") for _ in xrange(len(colors))] for _ in xrange(3)]
+        left[colors[0]-1][0] = 0
+        for i in xrange(1, len(colors)):
+            for color in xrange(3):
+                left[color][i] = left[color][i-1]+1
+            left[colors[i]-1][i] = 0
+
+        right = [[float("inf") for _ in xrange(len(colors))] for _ in xrange(3)]
+        right[colors[len(colors)-1]-1][len(colors)-1] = 0
+        for i in reversed(xrange(len(colors)-1)):
+            for color in xrange(3):
+                right[color][i] = right[color][i+1]+1
+            right[colors[i]-1][i] = 0
+         
+        return [min(left[color-1][i], right[color-1][i]) \
+                if min(left[color-1][i], right[color-1][i]) != float("inf") \
+                else -1 \
+                    for i, color in queries]
+