projecteuler solution 062

1 files changed, 57 insertions, 0 deletions

diff --git a/src/projecteuler/062.c b/src/projecteuler/062.c
new file mode 100644
index 0000000..4ba3350
--- /dev/null
+++ b/src/projecteuler/062.c
@@ -0,0 +1,57 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+struct number
+{
+	char digits[10];
+};
+
+const int cubecount = 30000;
+struct number* cubedigits;
+
+int main(void)
+{
+	int i, j;
+
+	cubedigits = (struct number*) malloc(cubecount*sizeof(struct number));
+	memset(cubedigits, 0, cubecount*sizeof(struct number));
+
+	for(i=1; i<cubecount; i++)
+	{
+		unsigned long long c = (unsigned long long)i*i*i;
+		int smallest = 0;
+		char count;
+
+		while(c > 0)
+		{
+			char digit = c % 10;
+			cubedigits[i].digits[digit]++;
+			c /= 10;
+		}
+
+		// search for permutations (i.e. same digits)
+		count = 0;
+		for(j=1; j<i; j++)
+		{
+			if(memcmp(cubedigits[i].digits, cubedigits[j].digits, sizeof(struct number)) == 0)
+			{
+				if(smallest == 0)
+					smallest = j;
+
+				count++;
+			}
+		}
+
+		if(count == 4) // 4 additional permutations
+		{
+			printf("%lli\n", (unsigned long long)smallest*smallest*smallest);
+			break;
+		}
+	}
+
+	free(cubedigits);
+
+	return 0;
+}
+