matrix_chain_mul

matrix_chain_mul.txt

@@ -0,0 +1,53 @@
+#include<stdio.h> 
+#include<limits.h> 
+
+// Matrix Ai has dimension p[i-1] x p[i] for i = 1..n 
+int MatrixChainOrder(int p[], int n) 
+{ 
+
+    /* For simplicity of the program, one extra row and one 
+       extra column are allocated in m[][].  0th row and 0th 
+       column of m[][] are not used */
+    int m[n][n]; 
+
+    int i, j, k, L, q; 
+
+    /* m[i,j] = Minimum number of scalar multiplications needed 
+       to compute the matrix A[i]A[i+1]...A[j] = A[i..j] where 
+       dimension of A[i] is p[i-1] x p[i] */
+
+    // cost is zero when multiplying one matrix. 
+    for (i=1; i<n; i++) 
+        m[i][i] = 0; 
+
+    // L is chain length. 
+    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-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]; 
+} 
+
+int main() 
+{ 
+    int arr[] = {1, 2, 3, 4}; 
+    int size = sizeof(arr)/sizeof(arr[0]); 
+
+    printf("Minimum number of multiplications is %d ", 
+                       MatrixChainOrder(arr, size)); 
+
+    getchar(); 
+    return 0; 
+}