Create 04 nthEleSpiralMatrix.cpp

04 Matrix/04 nthEleSpiralMatrix.cpp

@@ -0,0 +1,40 @@
+# Find nth element in a spiral matrix
+
+int findK(int matrix[MAX][MAX], int row, int col, int k)
+{
+
+    int x = 0;
+
+    int rs = 0, re = row-1, cs = 0, ce = col-1, tot = row*col;
+
+    while (x < (row*col)) {
+        for (int j = cs; j <= ce && x < tot; ++j) {
+            x++;
+            if (x == k) {
+                return matrix[rs][j];
+            }
+        }
+        rs++;
+        for (int i = rs; i <= re && x < tot; ++i) {
+            x++;
+            if (x == k) {
+                return matrix[i][ce];
+            }
+        }
+        ce--;
+        for (int j = ce; j >= cs && x < tot; --j) {
+            x++;
+            if (x == k) {
+                return matrix[re][j];
+            }
+        }
+        re--;
+        for (int i = re; i >= rs && x < tot; --i) {
+            x++;
+            if (x == k) {
+                return matrix[i][cs];
+            }
+        }
+        cs++;
+    }
+}