LeetCode/48.cc

userr2232 · Apr 10, 2022 · fafc805 · fafc805
1 parent fdfb4d4
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diff --git a/.DS_Store b/.DS_Store
diff --git a/LeetCode/48.cc b/LeetCode/48.cc
@@ -0,0 +1,30 @@
+class Solution {
+    void rotate(const int& start, const int& end, vector<vector<int>>& matrix) {
+        const int diff = end-start;
+        for(int m = 0; m < diff; m++) {
+            int i{start}, j{start+m};
+            int di{0}, dj{-1};
+            for(int k = 0; k < 3; ++k) {
+                int next_di{-dj}, next_dj{di};
+                int next_i{i+di*diff}, next_j{j+dj*diff};
+                int excess_i{next_i < start ? next_i-start : next_i > end ? next_i-end : 0};
+                int excess_j{next_j < start ? next_j-start : next_j > end ? next_j-end : 0};
+                next_i -= excess_i, next_j -= excess_j;
+                next_i += next_di * abs(excess_j), next_j += next_dj * abs(excess_i);
+                swap(matrix[i][j], matrix[next_i][next_j]);
+                di = next_di, dj = next_dj;
+                i = next_i, j = next_j;
+            }
+        }
+    }
+
+public:
+    void rotate(vector<vector<int>>& matrix) {
+        const int n = matrix.size();
+        int l{0}, r{n-1};
+        while(l < r) {
+            rotate(l, r, matrix);
+            l++, r--;
+        }
+    }
+};