Sum, Conditional Count, and Argmin

The three most common array-traversal computations — total sum, conditional count, and argmin — can run side by side in one loop. Each uses its own accumulator; all share the same iteration.

Combining them is more efficient than three separate loops and demonstrates clean accumulator discipline.

On the AP exam, these three patterns appear individually and in combination — and recognizing all three quickly is a sign of array fluency.

Combined template

int sum = 0;
int count = 0;
int minIndex = 0;
int minValue = arr[0];

for (int i = 0; i < arr.length; i++) {
    sum += arr[i];
    if (arr[i] > threshold) count++;
    if (arr[i] < minValue) {
        minValue = arr[i];
        minIndex = i;
    }
}

Initialization checklist

• Sum: 0.
• Count: 0.
• minValue: arr[0] (not 0 or Integer.MAX_VALUE for clarity).
• minIndex: 0.

Each pattern alone

// Sum only
int sum = 0;
for (int n : arr) sum += n;

// Conditional count only
int count = 0;
for (int n : arr) if (n > threshold) count++;

// Argmin only
int minIndex = 0;
for (int i = 1; i < arr.length; i++) {
    if (arr[i] < arr[minIndex]) minIndex = i;
}