index_list.c

//usr/bin/env gcc "$0" -o /tmp/_tmp_out && /tmp/_tmp_out; rm -f /tmp/_tmp_out; exit

#include <stdio.h>
#include <string.h>

enum { DATA_LEN = 100, INDEX_RANGE = 101 };

static void list_from_array(int *B, const int *A, size_t len) {
	memset(B, 0, sizeof(int) * INDEX_RANGE);
	B[0] = A[0];
	for (size_t i = 0; i < len - 1; i++)
		B[A[i]] = A[i + 1];
	B[A[len - 1]] = 0;
}

static void list_print(const int *B) {
	int v = B[0];
	while (v) {
		printf("%d ", v);
		v = B[v];
	}
	printf("\n");
}

static void list_sort(int *B) {
	int sorted = {0};
	int curr = B[0];
	B[0] = 0;
	while (curr) {
		int next = B[curr];
		if (sorted == 0 || curr > sorted) {
			B[curr] = sorted;
			sorted = curr;
		} else {
			int v = sorted;
			while (B[v] && B[v] > curr)
				v = B[v];
			B[curr] = B[v];
			B[v] = curr;
		}
		curr = next;
	}
	B[0] = sorted;
}

int main(void) {
	int A[DATA_LEN] = {0};
	for (size_t i = 0; i < DATA_LEN; i++)
		A[i] = i + 1;
	int B[INDEX_RANGE] = {0};
	list_from_array(B, A, DATA_LEN);
	list_print(B);
	list_sort(B);
	list_print(B);
}