New Commit

Author: coder-mayank22

matrix_chain_multi.c

@@ -1,63 +1,58 @@
+
 #include<stdio.h>
-#define inf 99999
-int n;
-int Chain_multi(int P[], int n) // P is the array of dimensions
+#include<limits.h>
+int N;
+void PrintOptimalParens(int s[][N], int i, int j);
+void MatrixChainOrder(int p[])
 {
-    int m[n][n];
-    int i, j, k, L, q;
+	int n = N - 1;
+	int m[n+1][n+1], s[n+1][n+1];
+	int i, l, j, k, q;
+	for(i=1;i<=n;i++)
+	m[i][i] = 0;
 
-    for (i = 1; i < n; i++)
-        m[i][i] = 0;
- 
-    for (L = 2; L < n; L++) {
-        for (i = 1; i < n - L + 1; i++) 
-        {
-            j = i + L - 1;
-            m[i][j] = inf;
-            for (k = i; k <= j - 1; k++) 
-            {
-                // q = cost/scalar multiplications
-                q = m[i][k] + m[k + 1][j]
-                    + P[i - 1] * P[k] * P[j];
-                if (q < m[i][j])
-                    m[i][j] = q;
-            }
-        }
-    }
- 
-    return m[1][n - 1];
+	for(l=2;l<=n;l++)
+	{
+		for(i=1;i<=n-l+1;i++)
+		{
+			j = i+l-1;
+			m[i][j] = INT_MAX;
+			for(k=i;k<j;k++)
+			{
+				q = m[i][k] + m[k+1][j] + p[i-1]*p[k]*p[j];
+				if(q<m[i][j])
+				{
+					m[i][j] = q;
+					s[i][j] = k;
+				}//if
+			}//k loop
+		}//i loop
+	}//l loop
+	printf("Minimum number of scalar multiplications: %d\n", m[1][n]);
+	PrintOptimalParens(s, 1, n);
 }
-
-void print_Optimal_parens(int s[n-1][n-1], int i, int j){
-    if(i==j)
-    printf("A%d", i);
-    else{
-        printf("(");
-        print_Optimal_parens(s, i, s[i][j]);
-        print_Optimal_parens(s, s[i][j]+1, j);
-        printf(")");
-    }
+void PrintOptimalParens(int s[][N], int i, int j)
+{
+	if(i==j)
+	printf("A%d ", i);
+	else
+	{
+		printf("(");
+		PrintOptimalParens(s, i, s[i][j]);
+		PrintOptimalParens(s, s[i][j]+1, j);
+		printf(")");
+	}//else
 }
 
-int main(){
-    int n, i, dim1, dim2;
-    printf("Enter number of matrices: ");
-    scanf("%d", &n);
-    int P[n+1];
-    printf("Enter dimensions of the matrices\n");
-    for(i=0;i<n;i++){
-        printf("Matrix A%d: ", i+1);
-        scanf("%d %d", &dim1, &dim2);
-        
-        P[i] = dim1;
-        P[i+1] = dim2;
-    }
-
-    for(i = 0; i<n+1; i++)printf("%d ", P[i]);
-    printf("\n");
-    int s[n-1][n-1];
-    int m = Chain_multi(P, n+1);
-    printf("\nMinimum number of multiplications = %d\n", m);
-    // print_Optimal_parens(s, 1, n);
-    return 0;
+int main()
+{
+	int i;
+	printf("Enter number of dimensions: ");
+	scanf("%d", &N);
+	int p[N];
+	printf("Enter dimensions:\n");
+	for(i=0;i<N;i++)
+	scanf("%d", &p[i]);
+	MatrixChainOrder(p);
+	return 0;
 }