problem-33

#include <stdio.h>

void optimalPageReplacement(int pages[], int n, int capacity) {
    int frames[capacity];
    for (int i = 0; i < capacity; i++) {
        frames[i] = -1;
    }

    int pageFaults = 0;

    for (int i = 0; i < n; i++) {
        int found = 0;
        for (int j = 0; j < capacity; j++) {
            if (frames[j] == pages[i]) {
                found = 1;
                break;
            }
        }

        if (!found) {
            if (frames[i % capacity] == -1) {
                frames[i % capacity] = pages[i];
            } else {
                int farthest = i + 1;
                int replaceIndex = -1;
                for (int j = 0; j < capacity; j++) {
                    int k;
                    for (k = i + 1; k < n; k++) {
                        if (frames[j] == pages[k]) {
                            if (k > farthest) {
                                farthest = k;
                                replaceIndex = j;
                            }
                            break;
                        }
                    }
                    if (k == n) {
                        replaceIndex = j;
                        break;
                    }
                }
                frames[replaceIndex] = pages[i];
            }
            pageFaults++;
        }

        printf("Page: %d -> Frames: ", pages[i]);
        for (int j = 0; j < capacity; j++) {
            if (frames[j] != -1) {
                printf("%d ", frames[j]);
            } else {
                printf("- ");
            }
        }
        printf("\n");
    }

    printf("Total Page Faults: %d\n", pageFaults);
}

int main() {
    int pages[] = {7, 0, 1, 2, 0, 3, 0, 4, 2, 3, 0, 3, 2};
    int n = sizeof(pages) / sizeof(pages[0]);
    int capacity = 3;

    optimalPageReplacement(pages, n, capacity);

    return 0;
}