Create 3337.py

Author: Chiki1601

3001-3500/3337.py

@@ -0,0 +1,35 @@
+class Solution(object):
+    mod = 10**9 + 7
+
+    def multiplyMatrices(self, A, B):
+        rowsA, colsA, colsB = len(A), len(A[0]), len(B[0])
+        result = [[0]*colsB for _ in range(rowsA)]
+        for i in range(rowsA):
+            for j in range(colsB):
+                tmp = 0
+                for k in range(colsA):
+                    tmp += A[i][k] * B[k][j]
+                result[i][j] = tmp % self.mod
+        return result
+
+    def powerMatrix(self, matrix, exponent):
+        n = len(matrix)
+        result = [[1 if i==j else 0 for j in range(n)] for i in range(n)]
+        while exponent > 0:
+            if exponent & 1:
+                result = self.multiplyMatrices(result, matrix)
+            matrix = self.multiplyMatrices(matrix, matrix)
+            exponent >>= 1
+        return result
+
+    def lengthAfterTransformations(self, s, t, nums):
+        transform = [[0]*26 for _ in range(26)]
+        for i in range(26):
+            for shift in range(nums[i]):
+                transform[i][(i + 1 + shift) % 26] += 1
+        transform = self.powerMatrix(transform, t)
+        freq = [[0]*26]
+        for ch in s:
+            freq[0][ord(ch) - ord('a')] += 1
+        freq = self.multiplyMatrices(freq, transform)
+        return sum(freq[0]) % self.mod