累加求和即从最小数开始一直加到最大数，例如：
1累加到100,即1+2+3……+100;
普通算法
1
2
3
| for(int i = min, i <= max; i++) {
sum += i;
}
|
下面是以扩展的形式开发的优化算法。
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
| #include <nan.h>
void change(long long *num1, long long *num2){
*num1 = *num2 + *num1;
*num2 = *num1 - *num2;
*num1 = *num1 - *num2;
}
long long add(long long min, long long max){
if (min > max) {
change(&min, &max);
}
long long sum = 0;
long long addTimes = 0;
if ((min + max) % 2 == 0) {
addTimes = (max - min) / 2;
return addTimes * (max + min ) + (max + min ) /2;
} else {
addTimes = (max - min + 1) / 2;
return (max+min)*addTimes;
}
}
void accumulation(const Nan::FunctionCallbackInfo<v8::Value>& info) {
if (info.Length() < 2) {
Nan::ThrowTypeError("至少需要两个参数");
return;
}
if (!info[0]->IsNumber() || !info[1]->IsNumber()) {
Nan::ThrowTypeError("错误的参数");
return;
}
long long arg0 = (long long) info[0]->NumberValue();
long long arg1 = (long long) info[1]->NumberValue();
long long sum = 0;
sum = add(arg0, arg1);
char buf[100];
sprintf(buf,"%lld",sum);
v8::Local<v8::String> num = Nan::New(buf).ToLocalChecked();
info.GetReturnValue().Set(num);
}
void Init(v8::Local<v8::Object> exports) {
exports->Set(Nan::New("accumulation").ToLocalChecked(),
Nan::New<v8::FunctionTemplate>(accumulation)->GetFunction());
}
NODE_MODULE(accumulation, Init)
|
建立binding.gyp
1
2
3
4
5
6
7
8
9
10
11
| {
"targets": [
{
"target_name": "accumulation",
"sources": [ "accumulation.cc" ],
"include_dirs": [
"<!(node -e \"require('nan')\")"
]
}
]
}
|
编译生成node扩展可以参照:http://blog.okgoes.com/index/blog/detail/uuid/1030000202/type/17/t/1496558300/bid/46.html
源码下载：https://github.com/zyw327/accumulation