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Commit d631bfb

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feat: update solutions to lc/lcof2 problem: Divide Two Integers
 * lcof2 No.001 * lc No.0029.Divide Two Integers
1 parent 3b6cd5a commit d631bfb

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11 files changed

+408
-76
lines changed

11 files changed

+408
-76
lines changed

‎lcof2/剑指 Offer II 001. 整数除法/README.md‎

Lines changed: 37 additions & 8 deletions
Original file line numberDiff line numberDiff line change
@@ -72,8 +72,8 @@ a = abs(a)
7272
b = abs(b)
7373
cnt = 0
7474
while a >= b:
75-
a -= b
76-
cnt += 1
75+
a -= b
76+
cnt += 1
7777
return sign * cnt
7878
```
7979

@@ -94,9 +94,8 @@ class Solution:
9494
tot = 0
9595
while a >= b:
9696
cnt = 0
97-
while a >= (b << cnt):
97+
while a >= (b << (cnt+1)):
9898
cnt += 1
99-
cnt -= 1
10099
tot += 1 << cnt
101100
a -= b << cnt
102101
return sign * tot if INT_MIN <= sign * tot <= INT_MAX else INT_MAX
@@ -118,10 +117,9 @@ class Solution {
118117
long tot = 0;
119118
while (x >= y) {
120119
int cnt = 0;
121-
while (x >= (y << cnt)) {
120+
while (x >= (y << (cnt+1))) {
122121
cnt++;
123122
}
124-
cnt--;
125123
tot += 1L << cnt;
126124
x -= y << cnt;
127125
}
@@ -156,10 +154,9 @@ func divide(a int, b int) int {
156154
tot := 0
157155
for a >= b {
158156
cnt := 0
159-
for a >= (b << cnt) {
157+
for a >= (b << (cnt + 1)) {
160158
cnt++
161159
}
162-
cnt--
163160
tot += 1 << cnt
164161
a -= b << cnt
165162
}
@@ -179,6 +176,38 @@ func abs(a int) int {
179176
}
180177
```
181178

179+
### **C++**
180+
181+
```cpp
182+
class Solution {
183+
public:
184+
int divide(int a, int b) {
185+
int sign = 1;
186+
if (a < 0 ^ b < 0) {
187+
sign = -1;
188+
}
189+
190+
auto x = abs(static_cast<long long>(a));
191+
auto y = abs(static_cast<long long>(b));
192+
auto tot = 0ll;
193+
while (x >= y) {
194+
int cnt = 0;
195+
while (x >= (y << (cnt + 1))) {
196+
++cnt;
197+
}
198+
tot += 1ll << cnt;
199+
x -= y << cnt;
200+
}
201+
202+
auto ans = sign * tot;
203+
if (ans >= INT32_MIN && ans <= INT32_MAX) {
204+
return static_cast<int>(ans);
205+
}
206+
return INT32_MAX;
207+
}
208+
};
209+
```
210+
182211
### **...**
183212

184213
```
Lines changed: 27 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,27 @@
1+
class Solution {
2+
public:
3+
int divide(int a, int b) {
4+
int sign = 1;
5+
if (a < 0 ^ b < 0) {
6+
sign = -1;
7+
}
8+
9+
auto x = abs(static_cast<long long>(a));
10+
auto y = abs(static_cast<long long>(b));
11+
auto tot = 0ll;
12+
while (x >= y) {
13+
int cnt = 0;
14+
while (x >= (y << (cnt + 1))) {
15+
++cnt;
16+
}
17+
tot += 1ll << cnt;
18+
x -= y << cnt;
19+
}
20+
21+
auto ans = sign * tot;
22+
if (ans >= INT32_MIN && ans <= INT32_MAX) {
23+
return static_cast<int>(ans);
24+
}
25+
return INT32_MAX;
26+
}
27+
};

‎lcof2/剑指 Offer II 001. 整数除法/Solution.go‎

Lines changed: 2 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -10,10 +10,9 @@ func divide(a int, b int) int {
1010
tot := 0
1111
for a >= b {
1212
cnt := 0
13-
for a >= (b << cnt) {
13+
for a >= (b << (cnt+1)) {
1414
cnt++
1515
}
16-
cnt--
1716
tot += 1 << cnt
1817
a -= b << cnt
1918
}
@@ -30,4 +29,4 @@ func abs(a int) int {
3029
return -a
3130
}
3231
return a
33-
}
32+
}

‎lcof2/剑指 Offer II 001. 整数除法/Solution.java‎

Lines changed: 2 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -9,10 +9,9 @@ public int divide(int a, int b) {
99
long tot = 0;
1010
while (x >= y) {
1111
int cnt = 0;
12-
while (x >= (y << cnt)) {
12+
while (x >= (y << (cnt + 1))) {
1313
cnt++;
1414
}
15-
cnt--;
1615
tot += 1L << cnt;
1716
x -= y << cnt;
1817
}
@@ -29,4 +28,4 @@ private long abs(long a) {
2928
}
3029
return a;
3130
}
32-
}
31+
}

‎lcof2/剑指 Offer II 001. 整数除法/Solution.py‎

Lines changed: 1 addition & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -8,9 +8,8 @@ def divide(self, a: int, b: int) -> int:
88
tot = 0
99
while a >= b:
1010
cnt = 0
11-
while a >= (b << cnt):
11+
while a >= (b << (cnt+1)):
1212
cnt += 1
13-
cnt -= 1
1413
tot += 1 << cnt
1514
a -= b << cnt
1615
return sign * tot if INT_MIN <= sign * tot <= INT_MAX else INT_MAX

‎solution/0000-0099/0029.Divide Two Integers/README.md‎

Lines changed: 127 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -41,22 +41,148 @@
4141

4242
<!-- 这里可写通用的实现逻辑 -->
4343

44+
通过下面这段伪代码,不难理解除法本质上就是减法,但是一次循环只能做一次减法,效率太低会导致超时,所以再加上快速幂的思想优化即可
45+
46+
```py
47+
sign = -1 if a * b < 0 else 1
48+
a = abs(a)
49+
b = abs(b)
50+
cnt = 0
51+
while a >= b:
52+
a -= b
53+
cnt += 1
54+
return sign * cnt
55+
```
56+
4457
<!-- tabs:start -->
4558

4659
### **Python3**
4760

4861
<!-- 这里可写当前语言的特殊实现逻辑 -->
4962

5063
```python
51-
64+
class Solution:
65+
def divide(self, a: int, b: int) -> int:
66+
INT_MAX = (1 << 31) - 1
67+
INT_MIN = -(1 << 31)
68+
sign = -1 if a * b < 0 else 1
69+
a = abs(a)
70+
b = abs(b)
71+
tot = 0
72+
while a >= b:
73+
cnt = 0
74+
while a >= (b << (cnt + 1)):
75+
cnt += 1
76+
tot += 1 << cnt
77+
a -= b << cnt
78+
return sign * tot if INT_MIN <= sign * tot <= INT_MAX else INT_MAX
5279
```
5380

5481
### **Java**
5582

5683
<!-- 这里可写当前语言的特殊实现逻辑 -->
5784

5885
```java
86+
class Solution {
87+
public int divide(int a, int b) {
88+
int sign = 1;
89+
if ((a < 0) != (b < 0)) {
90+
sign = -1;
91+
}
92+
long x = abs(a);
93+
long y = abs(b);
94+
long tot = 0;
95+
while (x >= y) {
96+
int cnt = 0;
97+
while (x >= (y << (cnt + 1))) {
98+
cnt++;
99+
}
100+
tot += 1L << cnt;
101+
x -= y << cnt;
102+
}
103+
long ans = sign * tot;
104+
if (ans >= Integer.MIN_VALUE && ans <= Integer.MAX_VALUE) {
105+
return (int) ans;
106+
}
107+
return Integer.MAX_VALUE;
108+
}
109+
110+
private long abs(long a) {
111+
if (a < 0) {
112+
return -a;
113+
}
114+
return a;
115+
}
116+
}
117+
```
118+
119+
### **Go**
120+
121+
```go
122+
func divide(a int, b int) int {
123+
sign := 1
124+
if a*b < 0 {
125+
sign = -1
126+
}
127+
128+
a = abs(a)
129+
b = abs(b)
130+
131+
tot := 0
132+
for a >= b {
133+
cnt := 0
134+
for a >= (b << (cnt + 1)) {
135+
cnt++
136+
}
137+
tot += 1 << cnt
138+
a -= b << cnt
139+
}
140+
141+
ans := sign * tot
142+
if ans >= math.MinInt32 && ans <= math.MaxInt32 {
143+
return ans
144+
}
145+
return math.MaxInt32
146+
}
147+
148+
func abs(a int) int {
149+
if a < 0 {
150+
return -a
151+
}
152+
return a
153+
}
154+
```
59155

156+
### **C++**
157+
158+
```cpp
159+
class Solution {
160+
public:
161+
int divide(int a, int b) {
162+
int sign = 1;
163+
if (a < 0 ^ b < 0) {
164+
sign = -1;
165+
}
166+
167+
auto x = abs(static_cast<long long>(a));
168+
auto y = abs(static_cast<long long>(b));
169+
auto tot = 0ll;
170+
while (x >= y) {
171+
int cnt = 0;
172+
while (x >= (y << (cnt + 1))) {
173+
++cnt;
174+
}
175+
tot += 1ll << cnt;
176+
x -= y << cnt;
177+
}
178+
179+
auto ans = sign * tot;
180+
if (ans >= INT32_MIN && ans <= INT32_MAX) {
181+
return static_cast<int>(ans);
182+
}
183+
return INT32_MAX;
184+
}
185+
};
60186
```
61187

62188
### **...**

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