Triangle

Signed-off-by: Leo Ma <[email protected]>

120_triangle/Makefile

@@ -0,0 +1,2 @@
+all:
+	gcc -O2 -o test triangle.c

120_triangle/triangle.c

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+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <string.h>
+
+static int recursive(int** triangle, int row_size, int *col_sizes,
+                     int row, int col, int **sums, bool **passes)
+{
+    if (row == row_size - 1) {
+        return triangle[row][col];
+    } else if (passes[row][col]) {
+        return sums[row][col];
+    } else {
+        int s1 = recursive(triangle, row_size, col_sizes, row + 1, col, sums, passes);
+        int s2 = recursive(triangle, row_size, col_sizes, row + 1, col + 1, sums, passes);
+        sums[row][col] = triangle[row][col] + (s1 < s2 ? s1 : s2);
+        passes[row][col] = true;
+        return sums[row][col];
+    }
+}
+
+static int minimumTotal(int** triangle, int triangleRowSize, int *triangleColSizes)
+{
+    int i;
+    bool **passes = malloc(triangleRowSize * sizeof(bool *));
+    for (i = 0; i < triangleRowSize; i++) {
+        passes[i] = malloc(triangleColSizes[i]);
+        memset(passes[i], false, triangleColSizes[i]);
+    }
+    int **sums = malloc(triangleRowSize * sizeof(int *));
+    for (i = 0; i < triangleRowSize; i++) {
+        sums[i] = malloc(triangleColSizes[i] * sizeof(int));
+    }
+    return recursive(triangle, triangleRowSize, triangleColSizes, 0, 0, sums, passes);
+}
+
+int main(void)
+{
+    int i, row = 4;
+    int **nums = malloc(row * sizeof(int *));
+    int *sizes = malloc(row * sizeof(int));
+    for (i = 0; i < row; i++) {
+        sizes[i] = i + 1;
+        nums[i] = malloc(sizes[i] * sizeof(int));
+    }
+#if 0
+    nums[0][0] = -1;
+    nums[1][0] = 3;
+    nums[1][1] = 2;
+    nums[2][0] = -3;
+    nums[2][1] = 1;
+    nums[2][2] = -1;
+#else
+    nums[0][0] = 2;
+    nums[1][0] = 3;
+    nums[1][1] = 4;
+    nums[2][0] = 6;
+    nums[2][1] = 5;
+    nums[2][2] = 7;
+    nums[3][0] = 4;
+    nums[3][1] = 1;
+    nums[3][2] = 8;
+    nums[3][3] = 3;
+#endif
+    printf("%d\n", minimumTotal(nums, row, sizes));
+    return 0;
+}