Add powMatrix function (#455)

graph.cpp

@@ -0,0 +1,32 @@
+#include "graph.h"
+#include <vector>
+
+// Implementation of powMatrix function
+std::vector<std::vector<int>> powMatrix(std::vector<std::vector<int>> A, int p) {
+    int n = A.size();
+    std::vector<std::vector<int>> result(n, std::vector<int>(n, 0));
+
+    // Initialize identity matrix
+    for(int i = 0; i < n; i++) result[i][i] = 1;
+
+    while(p) {
+        if(p % 2) {
+            std::vector<std::vector<int>> temp(n, std::vector<int>(n, 0));
+            for(int i = 0; i < n; i++)
+                for(int j = 0; j < n; j++)
+                    for(int k = 0; k < n; k++)
+                        temp[i][j] += result[i][k] * A[k][j];
+            result = temp;
+        }
+
+        std::vector<std::vector<int>> temp(n, std::vector<int>(n, 0));
+        for(int i = 0; i < n; i++)
+            for(int j = 0; j < n; j++)
+                for(int k = 0; k < n; k++)
+                    temp[i][j] += A[i][k] * A[k][j];
+        A = temp;
+        p /= 2;
+    }
+
+    return result;
+}

graph.h

@@ -0,0 +1,9 @@
+#ifndef GRAPH_H
+#define GRAPH_H
+
+#include <vector>
+
+// Declaration of powMatrix function
+std::vector<std::vector<int>> powMatrix(std::vector<std::vector<int>> A, int p);
+
+#endif