src/build-tx/coinselect-lib/inputs/bnb.js
function search(effectiveUtxos, target, costOfChange) {
    if (effectiveUtxos.length === 0) {
        return null;
    }

    let tries = maxTries;

    const selected = []; // true -> select the utxo at this index
    let selectedAccum = 0; // sum of effective values

    let done = false;
    let backtrack = false;

    let remaining = effectiveUtxos.reduce((a, x) => a + x.effectiveValue, 0);

    let depth = 0;
    while (!done) {
        if (tries <= 0) { // Too many tries, exit
            return null;
        }

        if (selectedAccum > target + costOfChange) {
            // Selected value is out of range, go back and try other branch
            backtrack = true;
        } else if (selectedAccum >= target) {
            // Selected value is within range
            done = true;
        } else if (depth >= effectiveUtxos.length) {
            // Reached a leaf node, no solution here
            backtrack = true;
        } else if (selectedAccum + remaining < target) {
            // Cannot possibly reach target with amount remaining
            if (depth === 0) {
                // At the first utxo, no possible selections, so exit
                return null;
            }
            backtrack = true;
        } else { // Continue down this branch
            // Remove this utxo from the remaining utxo amount
            remaining -= effectiveUtxos[depth].effectiveValue;
            // Inclusion branch first (Largest First Exploration)
            selected[depth] = true;
            selectedAccum += effectiveUtxos[depth].effectiveValue;
            depth++;
        }

        // Step back to the previous utxo and try the other branch
        if (backtrack) {
            backtrack = false; // Reset
            depth--;

            // Walk backwards to find the first utxo which has not has its second branch traversed
            while (!selected[depth]) {
                remaining += effectiveUtxos[depth].effectiveValue;

                // Step back one
                depth--;

                if (depth < 0) {
                    // We have walked back to the first utxo
                    // and no branch is untraversed. No solution, exit.
                    return null;
                }
            }

            // Now traverse the second branch of the utxo we have arrived at.
            selected[depth] = false;
            selectedAccum -= effectiveUtxos[depth].effectiveValue;
            depth++;
        }
        tries--;
    }

    return selected;
}
function search(effectiveUtxos, target, costOfChange) {
    if (effectiveUtxos.length === 0) {
        return null;
    }

    let tries = maxTries;

    const selected = []; // true -> select the utxo at this index
    let selectedAccum = 0; // sum of effective values

    let done = false;
    let backtrack = false;

    let remaining = effectiveUtxos.reduce((a, x) => a + x.effectiveValue, 0);

    let depth = 0;
    while (!done) {
        if (tries <= 0) { // Too many tries, exit
            return null;
        }

        if (selectedAccum > target + costOfChange) {
            // Selected value is out of range, go back and try other branch
            backtrack = true;
        } else if (selectedAccum >= target) {
            // Selected value is within range
            done = true;
        } else if (depth >= effectiveUtxos.length) {
            // Reached a leaf node, no solution here
            backtrack = true;
        } else if (selectedAccum + remaining < target) {
            // Cannot possibly reach target with amount remaining
            if (depth === 0) {
                // At the first utxo, no possible selections, so exit
                return null;
            }
            backtrack = true;
        } else { // Continue down this branch
            // Remove this utxo from the remaining utxo amount
            remaining -= effectiveUtxos[depth].effectiveValue;
            // Inclusion branch first (Largest First Exploration)
            selected[depth] = true;
            selectedAccum += effectiveUtxos[depth].effectiveValue;
            depth++;
        }

        // Step back to the previous utxo and try the other branch
        if (backtrack) {
            backtrack = false; // Reset
            depth--;

            // Walk backwards to find the first utxo which has not has its second branch traversed
            while (!selected[depth]) {
                remaining += effectiveUtxos[depth].effectiveValue;

                // Step back one
                depth--;

                if (depth < 0) {
                    // We have walked back to the first utxo
                    // and no branch is untraversed. No solution, exit.
                    return null;
                }
            }

            // Now traverse the second branch of the utxo we have arrived at.
            selected[depth] = false;
            selectedAccum -= effectiveUtxos[depth].effectiveValue;
            depth++;
        }
        tries--;
    }

    return selected;
}
Depth first search Inclusion branch first (Largest First Exploration), then exclusion branch