/** * 大整數求和 * @param bigNumberA 大整數A * @param bigNumberB 大整數B */public static String bigNumberSum(String bigNumberA, String bigNumberB) { //1.把兩個大整數用陣列逆序儲存，陣列長度等於較大整數位數+1 int maxLength = bigNumberA.length() > bigNumberB.length() ? bigNumberA.length() : bigNumberB.length(); int[] arrayA = new int[maxLength+1]; for(int i=0; i< bigNumberA.length(); i++){ arrayA[i] = bigNumberA.charAt(bigNumberA.length()-1-i) - ‘0’; } int[] arrayB = new int[maxLength+1]; for(int i=0; i< bigNumberB.length(); i++){ arrayB[i] = bigNumberB.charAt(bigNumberB.length()-1-i) - ‘0’; }

//2.構建result陣列，陣列長度等於較大整數位數+1 int[] result = new int[maxLength+1]; //3.遍歷陣列，按位相加 for(int i=0; i<result.length; i++){ int temp = result[i]; temp += arrayA[i]; temp += arrayB[i]; //判斷是否進位 if(temp >= 10){ temp = temp-10; result[i+1] = 1; } result[i] = temp; } //4.把result陣列再次逆序並轉成String StringBuilder sb = new StringBuilder(); //是否找到大整數的最高有效位 boolean findFirst = false; for (int i = result.length - 1; i >= 0; i–) { if(!findFirst){ if(result[i] == 0){ continue; } findFirst = true; } sb.append(result[i]); } return sb.toString();}public static void main(String[] args) { System.out.println(bigNumberSum(“426709752318”, “95481253129”));}