src/vs/base/common/diff/diff.ts/LcsDiff/_findBetterContiguousSequence
class LcsDiff:	private _findBetterContiguousSequence(originalStart: number, originalLength: number, modifiedStart: number, modifiedLength: number, desiredLength: number): [number, number] | null {
		if (originalLength < desiredLength || modifiedLength < desiredLength) {
			return null;
		}
		const originalMax = originalStart + originalLength - desiredLength + 1;
		const modifiedMax = modifiedStart + modifiedLength - desiredLength + 1;
		let bestScore = 0;
		let bestOriginalStart = 0;
		let bestModifiedStart = 0;
		for (let i = originalStart; i < originalMax; i++) {
			for (let j = modifiedStart; j < modifiedMax; j++) {
				const score = this._contiguousSequenceScore(i, j, desiredLength);
				if (score > 0 && score > bestScore) {
					bestScore = score;
					bestOriginalStart = i;
					bestModifiedStart = j;
				}
			}
		}
		if (bestScore > 0) {
			return [bestOriginalStart, bestModifiedStart];
		}
		return null;
	}