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export default function findCircleNum(isConnected: number[][]): number {    const m = isConnected.length;    if (m === 0) return 0;    const n = isConnected[0].length;    if (n === 0) return 0;    const cache = new Set<number>();    let provinces = 0;
    for (let i = 0; i < m; i++) {        if (!cache.has(i)) {            provinces++;            dfs(i);        }    }    function dfs(i: number) {        if (cache.has(i)) {            return;        }        cache.add(i);
        for (            const [j] of [...isConnected[i].entries()].filter(                ([j, v]) => v === 1 && i !== j,            )        ) {            dfs(j);        }    }    return provinces;}