Solution.ts

function findString(words: string[], s: string): number {
    const dfs = (i: number, j: number): number => {
        if (i > j) {
            return -1;
        }
        const mid = (i + j) >> 1;
        const l = dfs(i, mid - 1);
        if (l !== -1) {
            return l;
        }
        if (words[mid] === s) {
            return mid;
        }
        return dfs(mid + 1, j);
    };
    return dfs(0, words.length - 1);
}