Create demonetization.c

Ways to dispense currency by ATM machine involving recursion.

misc/demonetization.c

@@ -0,0 +1,24 @@
+// Recursion problem
+//Given the denominations of currencies available in a system, find the number of ways an ATM machine can
+//generate notes for an entered amount N.
+
+#include <stdio.h>
+
+int ways(int n, int a[], int k) {
+    if(n<0 || k<0) return 0;
+    if(n == 0) return 1;
+    if(k == 0) return 0;
+    return ways(n, a, k-1) + ways(n-a[k-1], a, k);
+}
+
+int main() {
+    int m; scanf("%d", &m);
+    int coin[m], i; for(i=0; i<m; i++) scanf("%d", &coin[i]);
+
+    int t; scanf("%d", &t);
+    while(t--) {
+        int n; scanf("%d", &n);
+        printf("%d\n", ways(n, coin, m));
+    }
+    return 0;
+}