Here's the rewritten version with tail recursion and memoization:

```C
#define MAX 100
int fib(int n, int memo[]) {
    if (memo[n] != -1) {
        return memo[n];
    }

    if (n <= 1) {
        return n;
    }

    int result = fib(n - 1, memo) + fib(n - 2, memo);
    memo[n] = result;

    return result;
}

int fibonacci(int n) {
    int memo[MAX];
    int i;

    // Initialize memoization array with -1
    for (i = 0; i < MAX; i++) {
        memo[i] = -1;
    }

    return fib(n, memo);
}
```
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