腾讯云前端一面面经
算法题
大数相加
代码
function addBigNum(str1, str2){ let res = '', c = 0; const str1Arr = str1.split(''), str2Arr = str2.split(''); while(str1Arr.length || str2Arr.length || c){ const num1 = str1Arr.length ? str1Arr.pop() : 0, num2 = str2Arr.length ? str2Arr.pop() : 0; c += num1 + num2; res = (c % 10) + res; c = c > 9; } return res.replace(/^0+/,''); }
最大子序和
给定一个数组,找到一个具有最大和的连续子数组,返回其最大和。示例如下
输入:
1,-2,4,5,-1,1
输出:
9
最大子数组:
[4,5]
代码
function largestSum(arr) { if (!arr) return null; const len = arr.length; if (!len) return Number.MIN_SAFE_INTEGER; let sum = arr[0]; let res = sum; for (let i = 1; i < len; i++) { if (sum < 0) sum = arr[i]; else sum = sum + arr[i]; res = Math.max(res, sum); } return res; } console.log(largestSum([1,2,4,5,-1,1]));
子字符串匹配
给定两个字符串 s 和 t,其中 t 是 s 的子字符串。s的子字符串是字符都取自s,并且保持在s中的位置的相对顺序,但不需要是连续的。比如,s="abcdef",t="bd"。
要求找出 t 在 s 中匹配的子字符串数量。
比如:
Input: s = "rabbbit", t = "rabbit" Output: 3 Explanation: As shown below, there are 3 ways you can generate "rabbit" from S. rabbbit rabbbit rabbbit
[输入]
"babgbag" "bag"
[输出]
5
[输入]
"rabbbit" "rabbit"
[输出]
3
[输入]
"xslledayhxhadmctrliaxqpokyezcfhzaskeykchkmhpyjipxtsuljkwkovmvelvwxzwieeuqnjozrfwmzsylcwvsthnxujvrkszqwtglewkycikdaiocglwzukwovsghkhyidevhbgffoqkpabthmqihcfxxzdejletqjoxmwftlxfcxgxgvpperwbqvhxgsbbkmphyomtbjzdjhcrcsggleiczpbfjcgtpycpmrjnckslrwduqlccqmgrdhxolfjafmsrfdghnatexyanldrdpxvvgujsztuffoymrfteholgonuaqndinadtumnuhkboyzaqguwqijwxxszngextfcozpetyownmyneehdwqmtpjloztswmzzdzqhuoxrblppqvyvsqhnhryvqsqogpnlqfulurexdtovqpqkfxxnqykgscxaskmksivoazlducanrqxynxlgvwonalpsyddqmaemcrrwvrjmjjnygyebwtqxehrclwsxzylbqexnxjcgspeynlbmetlkacnnbhmaizbadynajpibepbuacggxrqavfnwpcwxbzxfymhjcslghmajrirqzjqxpgtgisfjreqrqabssobbadmtmdknmakdigjqyqcruujlwmfoagrckdwyiglviyyrekjealvvigiesnvuumxgsveadrxlpwetioxibtdjblowblqvzpbrmhupyrdophjxvhgzclidzybajuxllacyhyphssvhcffxonysahvzhzbttyeeyiefhunbokiqrpqfcoxdxvefugapeevdoakxwzykmhbdytjbhigffkmbqmqxsoaiomgmmgwapzdosorcxxhejvgajyzdmzlcntqbapbpofdjtulstuzdrffafedufqwsknumcxbschdybosxkrabyfdejgyozwillcxpcaiehlelczioskqtptzaczobvyojdlyflilvwqgyrqmjaeepydrcchfyftjighntqzo... "rwmimatmhydhbujebqehjprrwfkoebcxxqfktayaaeheys"
[输出]
543744000
代码,注释部分未优化路径,
// function searchWord(s, t) { // const sLen = s.length, tLen = t.length; // const dp = new Array(sLen + 1); // for (let i = 0; i <= sLen; i++) { // dp[i] = new Array(tLen + 1).fill(0); // } // dp[0][0] = 1; // for (let i = 1; i <= sLen; i++) { // dp[i][0] = 1; // for (let j = 1; j <= tLen; j++) { // if (s[i - 1] === t[j - 1]) { // dp[i][j] = dp[i - 1][j - 1] + dp[i - 1][j]; // } else { // dp[i][j] = dp[i - 1][j]; // } // } // } // return dp[sLen][tLen]; // } function searchWord(s, t) { const sLen = s.length, tLen = t.length; const dp = new Array(tLen + 1).fill(0); dp[0] = 1; for (let i = 1; i <= sLen; i++) { let pre = 1; for (let j = 1; j <= tLen; j++) { let temp = dp[j]; if (s[i - 1] === t[j - 1]) { dp[j] += pre; } pre = temp; } } return dp[tLen]; } const s = "rabit", t = "rabbit"; console.log(searchWord(s, t));