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Commit d05dc03

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feat: add solutions to lc problem: No.0371
No.0371.Sum of Two Integers
1 parent 312983b commit d05dc03

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10 files changed

+168
-18
lines changed

10 files changed

+168
-18
lines changed

‎lcof/面试题65. 不用加减乘除做加法/README.md‎

Lines changed: 22 additions & 7 deletions
Original file line numberDiff line numberDiff line change
@@ -50,11 +50,9 @@
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class Solution:
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def add(self, a: int, b: int) -> int:
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a, b = a & 0xffffffff, b & 0xffffffff
53-
s = carry = 0
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while b:
55-
s = a ^ b
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carry = ((a & b) << 1) & 0xffffffff
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a, b = s, carry
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a, b = a ^ b, carry
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return a if a < 0x80000000 else ~(a ^ 0xffffffff)
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```
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@@ -88,6 +86,23 @@ class Solution {
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}
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```
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### **C++**
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```cpp
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class Solution {
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public:
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int add(int a, int b) {
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while (b)
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{
97+
unsigned int carry = (unsigned int)(a & b) << 1;
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a = a ^ b;
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b = carry;
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}
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return a;
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}
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};
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```
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### **JavaScript**
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```js
@@ -106,10 +121,10 @@ var add = function (a, b) {
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```go
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func add(a int, b int) int {
109-
if b == 0 {
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return a
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}
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return add(a ^ b, (a & b) << 1)
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if b == 0 {
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return a
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}
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return add(a^b, (a&b)<<1)
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}
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```
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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,12 @@
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class Solution {
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public:
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int add(int a, int b) {
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while (b)
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{
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unsigned int carry = (unsigned int)(a & b) << 1;
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a = a ^ b;
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b = carry;
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}
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return a;
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}
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};
Lines changed: 4 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -1,6 +1,6 @@
11
func add(a int, b int) int {
2-
if b == 0 {
3-
return a
4-
}
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return add(a^b, (a&b) <<1)
2+
if b == 0 {
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return a
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}
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return add(a^b, (a&b)<<1)
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}
Lines changed: 2 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -1,9 +1,7 @@
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class Solution:
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def add(self, a: int, b: int) -> int:
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a, b = a & 0xffffffff, b & 0xffffffff
4-
s = carry = 0
54
while b:
6-
s = a ^ b
75
carry = ((a & b) << 1) & 0xffffffff
8-
a, b = s, carry
9-
return a if a < 0x80000000 else ~(a ^ 0xffffffff)
6+
a, b = a^b, carry
7+
return a if a < 0x80000000 else ~(a ^ 0xffffffff)

‎solution/0300-0399/0371.Sum of Two Integers/README.md‎

Lines changed: 59 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -23,22 +23,80 @@
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<!-- 这里可写通用的实现逻辑 -->
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两数字的二进制形式 a,b ,求和 s = a + b ,a(i)、b(i) 分别表示 a、b 的第 i 个二进制位。一共有 4 种情况:
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| a(i) | b(i) | 不进位的和 | 进位 |
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| ---- | ---- | ---------- | ---- |
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| 0 | 0 | 0 | 0 |
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| 0 | 1 | 1 | 0 |
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| 1 | 0 | 1 | 0 |
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| 1 | 1 | 0 | 1 |
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观察可以发现,"不进位的和"与"异或运算"有相同规律,而进位则与"与"运算规律相同,并且需要左移一位。
36+
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- 对两数进行按位 `^` 异或运算,得到不进位的和;
38+
- 对两数进行按位 `&` 与运算,然后左移一位,得到进位;
39+
- 问题转换为求:"不进位的数 + 进位" 之和;
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- 循环,直至进位为 0,返回不进位的数即可(也可以用递归实现)。
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2642
<!-- tabs:start -->
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### **Python3**
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<!-- 这里可写当前语言的特殊实现逻辑 -->
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32-
```python
48+
由于 python `int` 是无限长整型,左移不会自动溢出,因此需要特殊处理。
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```python
51+
class Solution:
52+
def getSum(self, a: int, b: int) -> int:
53+
a, b = a & 0xffffffff, b & 0xffffffff
54+
while b:
55+
carry = ((a & b) << 1) & 0xffffffff
56+
a, b = a ^ b, carry
57+
return a if a < 0x80000000 else ~(a ^ 0xffffffff)
3458
```
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### **Java**
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<!-- 这里可写当前语言的特殊实现逻辑 -->
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4064
```java
65+
class Solution {
66+
public int getSum(int a, int b) {
67+
return b == 0 ? a : getSum(a ^ b, (a & b) << 1);
68+
}
69+
}
70+
```
71+
72+
### **C++**
73+
74+
```cpp
75+
class Solution {
76+
public:
77+
int getSum(int a, int b) {
78+
while (b)
79+
{
80+
unsigned int carry = (unsigned int)(a & b) << 1;
81+
a = a ^ b;
82+
b = carry;
83+
}
84+
return a;
85+
}
86+
};
87+
```
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### **Go**
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```go
92+
func getSum(a int, b int) int {
93+
for b != 0 {
94+
s := a ^ b
95+
b = (a & b) << 1
96+
a = s
97+
}
98+
return a
99+
}
42100
```
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44102
### **...**

‎solution/0300-0399/0371.Sum of Two Integers/README_EN.md‎

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Original file line numberDiff line numberDiff line change
@@ -28,13 +28,53 @@
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### **Python3**
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```python
31-
31+
class Solution:
32+
def getSum(self, a: int, b: int) -> int:
33+
a, b = a & 0xffffffff, b & 0xffffffff
34+
while b:
35+
carry = ((a & b) << 1) & 0xffffffff
36+
a, b = a ^ b, carry
37+
return a if a < 0x80000000 else ~(a ^ 0xffffffff)
3238
```
3339

3440
### **Java**
3541

3642
```java
43+
class Solution {
44+
public int getSum(int a, int b) {
45+
return b == 0 ? a : getSum(a ^ b, (a & b) << 1);
46+
}
47+
}
48+
```
49+
50+
### **C++**
51+
52+
```cpp
53+
class Solution {
54+
public:
55+
int getSum(int a, int b) {
56+
while (b)
57+
{
58+
unsigned int carry = (unsigned int)(a & b) << 1;
59+
a = a ^ b;
60+
b = carry;
61+
}
62+
return a;
63+
}
64+
};
65+
```
3766
67+
### **Go**
68+
69+
```go
70+
func getSum(a int, b int) int {
71+
for b != 0 {
72+
s := a ^ b
73+
b = (a & b) << 1
74+
a = s
75+
}
76+
return a
77+
}
3878
```
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### **...**
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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,12 @@
1+
class Solution {
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public:
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int getSum(int a, int b) {
4+
while (b)
5+
{
6+
unsigned int carry = (unsigned int)(a & b) << 1;
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a = a ^ b;
8+
b = carry;
9+
}
10+
return a;
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}
12+
};
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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,8 @@
1+
func getSum(a int, b int) int {
2+
for b != 0 {
3+
s := a ^ b
4+
b = (a & b) << 1
5+
a = s
6+
}
7+
return a
8+
}

‎solution/0300-0399/0371.Sum of Two Integers/Solution.java‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -2,4 +2,4 @@ class Solution {
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public int getSum(int a, int b) {
33
return b == 0 ? a : getSum(a ^ b, (a & b) << 1);
44
}
5-
}
5+
}
Lines changed: 7 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,7 @@
1+
class Solution:
2+
def getSum(self, a: int, b: int) -> int:
3+
a, b = a & 0xffffffff, b & 0xffffffff
4+
while b:
5+
carry = ((a & b) << 1) & 0xffffffff
6+
a, b = a ^ b, carry
7+
return a if a < 0x80000000 else ~(a ^ 0xffffffff)

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