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leetcode_java/src/main/java/LeetCodeJava/BitManipulation/SumOfTwoIntegers.java
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| @@ -0,0 +1,133 @@ | ||
| package LeetCodeJava.BitManipulation; | ||
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| // https://leetcode.com/problems/sum-of-two-integers/description/ | ||
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| public class SumOfTwoIntegers { | ||
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| // V0 | ||
| // IDEA : BIT OP | ||
| // TODO : fix below | ||
| // public int getSum(int a, int b) { | ||
| // | ||
| // if (a == 0 && b == 0){ | ||
| // return 0; | ||
| // } | ||
| // | ||
| // if (a == 0 || b == 0){ | ||
| // if (a == 0){ | ||
| // return b; | ||
| // } | ||
| // return a; | ||
| // } | ||
| // | ||
| // // bit op | ||
| // String aBin = Integer.toBinaryString(a); | ||
| // String bBin = Integer.toBinaryString(b); | ||
| // | ||
| // String res = addBinary(aBin, bBin); | ||
| // return Integer.parseInt(res, 2); | ||
| // } | ||
| // | ||
| // public static String addBinary(String a, String b) { | ||
| // StringBuilder sb = new StringBuilder(); | ||
| // int i = a.length() - 1, j = b.length() - 1, carry = 0; | ||
| // while (i >= 0 || j >= 0 || carry > 0) { | ||
| // int sum = carry; | ||
| // if (i >= 0) sum += a.charAt(i--) - '0'; | ||
| // if (j >= 0) sum += b.charAt(j--) - '0'; | ||
| // sb.append(sum % 2); | ||
| // carry = sum / 2; | ||
| // } | ||
| // return sb.reverse().toString(); | ||
| // } | ||
| // | ||
| //// private int add(String x, String y){ | ||
| //// | ||
| //// int len = Math.max(x.length(), y.length()); | ||
| //// if (len > x.length()){ | ||
| //// x = (multiplyStr("0", len - x.length()) + x); | ||
| //// }else{ | ||
| //// y = (multiplyStr("0", len - x.length()) + y); | ||
| //// } | ||
| //// | ||
| //// System.out.println("x = " + x + " y = " + y); | ||
| //// | ||
| //// String res = ""; | ||
| //// | ||
| //// int plus = 0; | ||
| //// for (int j = x.length()-1; j >= 0; j --){ | ||
| //// System.out.println("x.indexOf(j) = " + x.indexOf(j)); | ||
| //// int cur = Integer.parseInt(String.valueOf(x.indexOf(j))) + Integer.parseInt(String.valueOf(y.indexOf(j))) + plus; | ||
| //// System.out.println("cur = " + cur); | ||
| //// if (cur > 1){ | ||
| //// cur -= 2; | ||
| //// plus = 1; | ||
| //// res += cur; | ||
| //// }else{ | ||
| //// res += cur; | ||
| //// } | ||
| //// } | ||
| //// | ||
| //// if (plus != 0){ | ||
| //// res = "1" + res; | ||
| //// } | ||
| //// | ||
| //// // convert a Binary String to a base 10 integer in Java | ||
| //// // https://stackoverflow.com/questions/10178980/how-to-convert-a-binary-string-to-a-base-10-integer-in-java | ||
| //// | ||
| //// System.out.println("res = " + res); | ||
| //// return Integer.parseInt(res, 2); | ||
| //// } | ||
| // | ||
| // // https://stackoverflow.com/questions/2255500/can-i-multiply-strings-in-java-to-repeat-sequences | ||
| // private static String multiplyStr(String s, int multiply){ | ||
| // StringBuilder r = new StringBuilder(); | ||
| // for (int i = 0; i < multiply; i++){ | ||
| // r.append(s); | ||
| // } | ||
| // return r.toString(); | ||
| // } | ||
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| // V1 | ||
| // IDEA : BIT OP | ||
| // https://leetcode.com/problems/sum-of-two-integers/solutions/4623531/java-best-easy-solution-100-beats-0ms/ | ||
| public int getSum_1(int a, int b) { | ||
| while(b!=0) | ||
| { | ||
| int carry=a&b; | ||
| a=a ^ b; | ||
| b=carry<<1; | ||
| } | ||
| return a; | ||
| } | ||
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| // V2 | ||
| // https://leetcode.com/problems/sum-of-two-integers/solutions/84290/java-simple-easy-understand-solution-with-explanation/ | ||
| // Iterative | ||
| public int getSum_2(int a, int b) { | ||
| if (a == 0) return b; | ||
| if (b == 0) return a; | ||
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| while (b != 0) { | ||
| int carry = a & b; | ||
| a = a ^ b; | ||
| b = carry << 1; | ||
| } | ||
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| return a; | ||
| } | ||
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| // V3 | ||
| // https://leetcode.com/problems/sum-of-two-integers/solutions/84290/java-simple-easy-understand-solution-with-explanation/ | ||
| // Iterative | ||
| public int getSubtract_3(int a, int b) { | ||
| while (b != 0) { | ||
| int borrow = (~a) & b; | ||
| a = a ^ b; | ||
| b = borrow << 1; | ||
| } | ||
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| return a; | ||
| } | ||
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| } |