How to use JavaScript BigInt and Number.prototype.toString to handle the super large integer problems All In One

如何使用 JavaScript BigInt 和 Number.prototype.toStringg 处理超大整数问题

errors

function plusOne(digits: number[]): number[] {
  let n = parseInt(digits.join(``));
  return `${n + 1}`.split(``).map(Number);
};
//  // 大数相加超出 JavaScript 中的最大安全整数 (2**53 – 1) 最大值 bug ❌ 

solutions

function plusOne(digits: number[]): number[] {
  const arr: number[] = digits;
  // 进位 
  let inc = 1;
  for (let i = arr.length - 1; i >= 0; i--) {
    const n = arr[i] + inc;
    if(n >= 10 && inc) {
      arr[i] = n - 10;
      inc = 1;
    } else {
      arr[i] = n;
      inc = 0;
    }
  }
  // 最高一位进位
  if(inc) {
    arr.unshift(inc);
  }
  return arr;
};

function plusOne(digits: number[]): number[] {
  let rest: number = 1;
  let temp: number = 0;
  for(let i = digits.length -1; i >= 0; i--) {
    temp = digits[i] + rest;
    rest = temp > 9 ? 1 : 0;
    digits[i] = temp > 9 ? 0 : temp;
  }
  // 插入 1 进位
  if(rest) {
    digits.unshift(1);
  }
  return digits;
};

function plusOne(digits: number[]): number[] {
  return (BigInt(digits.join(``)) + BigInt(1)).toString().split(``).map(Number);
};

demos

function plusOne(digits: number[]): number[] {
  let rest: number = 1;
  let temp: number = 0;
  for(let i = digits.length -1; i >= 0; i--) {
    temp = digits[i] + rest;
    rest = temp > 9 ? 1 : 0; 
    digits[i] = temp > 9 ? 0 : temp; 
  }
  // 插入 1 进位
  if(rest) {
    digits.unshift(1);
  }
  return digits;
};


// BigInt ❓ https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigInt



// 大数相加超出 JavaScript 中的最大安全整数 (2**53 – 1) 最大值 bug ❌ 

/* 

6145390195186705543 + 1
// 6145390195186705000

 */

// function plusOne(digits: number[]): number[] {
//   let n = parseInt(digits.join(``));
//   return `${n + 1}`.split(``).map(Number);
// };


/* 

Wrong Answer
71 / 111 testcases passed

Input
digits =
[6,1,4,5,3,9,0,1,9,5,1,8,6,7,0,5,5,4,3]

Output
[6,1,4,5,3,9,0,1,9,5,1,8,6,7,0,5,0,0,0]
Expected
[6,1,4,5,3,9,0,1,9,5,1,8,6,7,0,5,5,4,4]

 */

https://leetcode.com/problems/plus-one/description/

BigInt

digits = [6,1,4,5,3,9,0,1,9,5,1,8,6,7,0,5,5,4,3]
// (19) [6, 1, 4, 5, 3, 9, 0, 1, 9, 5, 1, 8, 6, 7, 0, 5, 5, 4, 3]
BigInt(digits.join(''))
// 6145390195186705543n

BigInt(digits.join('')).toString().split("").map(Number)
// (19) [6, 1, 4, 5, 3, 9, 0, 1, 9, 5, 1, 8, 6, 7, 0, 5, 5, 4, 3]

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigInt

Number.MAX_SAFE_INTEGER

The Number.MAX_SAFE_INTEGER static data property represents the maximum safe integer in JavaScript (2**53 – 1).

Number.MAX_SAFE_INTEGER 静态数据属性表示 JavaScript 中的最大安全整数 (2**53 – 1)。

Number.MAX_SAFE_INTEGER
9007199254740991
2 ** 64 - 1
18446744073709552000
2 ** 32 - 1
4294967295

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/MAX_SAFE_INTEGER

refs

https://stackoverflow.com/questions/51984393/why-i-cant-convert-string-to-number-without-losing-precision-in-js

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