#ifndef THING_H_ #define THING_H_ #include <iostream> #include <string> using namespace std; class Thing { public: Thing(int n) : m_Num(n) { } ~Thing() { cout << "destructor called: " << m_Num << endl; } private: string m_String; int m_Num; }; #endif
榪愯緇撴灉
destructor called: 107 destructor called: 106 destructor called: 101 destructor called: 104 destructor called: 103 destructor called: 102 destructor called: 101
]]>
C++ 榪愮畻絎︿紭鍏堢駭鍒楄〃
http://www.cppreference.com/operator_precedence.html| Precedence | Operator | Description | Example | Associativity |
|---|---|---|---|---|
| 1 | () [] -> . :: ++ -- |
Grouping operator Array access Member access from a pointer Member access from an object Scoping operator Post-increment Post-decrement |
(a + b) / 4; array[4] = 2; ptr->age = 34; obj.age = 34; Class::age = 2; for( i = 0; i < 10; i++ ) ... for( i = 10; i > 0; i-- ) ... |
left to right |
| 2 | ! ~ ++ -- - + * & (type) sizeof |
Logical negation Bitwise complement Pre-increment Pre-decrement Unary minus Unary plus Dereference Address of Cast to a given type Return size in bytes |
if( !done ) ... flags = ~flags; for( i = 0; i < 10; ++i ) ... for( i = 10; i > 0; --i ) ... int i = -1; int i = +1; data = *ptr; address = &obj; int i = (int) floatNum; int size = sizeof(floatNum); |
right to left |
| 3 | ->* .* |
Member pointer selector Member pointer selector |
ptr->*var = 24; obj.*var = 24; |
left to right |
| 4 | * / % |
Multiplication Division Modulus |
int i = 2 * 4; float f = 10 / 3; int rem = 4 % 3; |
left to right |
| 5 | + - |
Addition Subtraction |
int i = 2 + 3; int i = 5 - 1; |
left to right |
| 6 | << >> |
Bitwise shift left Bitwise shift right |
int flags = 33 << 1; int flags = 33 >> 1; |
left to right |
| 7 | < <= > >= |
Comparison less-than Comparison less-than-or-equal-to Comparison greater-than Comparison geater-than-or-equal-to |
if( i < 42 ) ... if( i <= 42 ) ... if( i > 42 ) ... if( i >= 42 ) ... |
left to right |
| 8 | == != |
Comparison equal-to Comparison not-equal-to |
if( i == 42 ) ... if( i != 42 ) ... |
left to right |
| 9 | & | Bitwise AND | flags = flags & 42; | left to right |
| 10 | ^ | Bitwise exclusive OR | flags = flags ^ 42; | left to right |
| 11 | | | Bitwise inclusive (normal) OR | flags = flags | 42; | left to right |
| 12 | && | Logical AND | if( conditionA && conditionB ) ... | left to right |
| 13 | || | Logical OR | if( conditionA || conditionB ) ... | left to right |
| 14 | ? : | Ternary conditional (if-then-else) | int i = (a > b) ? a : b; | right to left |
| 15 | = += -= *= /= %= &= ^= |= <<= >>= |
Assignment operator Increment and assign Decrement and assign Multiply and assign Divide and assign Modulo and assign Bitwise AND and assign Bitwise exclusive OR and assign Bitwise inclusive (normal) OR and assign Bitwise shift left and assign Bitwise shift right and assign |
int a = b; a += 3; b -= 4; a *= 5; a /= 2; a %= 3; flags &= new_flags; flags ^= new_flags; flags |= new_flags; flags <<= 2; flags >>= 2; |
right to left |
| 16 | , | Sequential evaluation operator | for( i = 0, j = 0; i < 10; i++, j++ ) ... | left to right |
]]>
#include<iostream>
#include<algorithm>
#include <functional>
using namespace std;
int data[1010];
int main()
{
int n,m;
while(scanf("%d%d",&n,&m)!=EOF)
{
for(int i = 0; i < n; i ++)
data[i] = i+1;
sort(data,data+n);
m --;
while(m--)
next_permutation(data,data+n);
for( i = 0;i<n;i++)
printf(i ==0 ?"%d":" %d",data[i]);
printf("\n");
}
return 0;
}
]]>
榪欓噷鍒欓渶瑕?6MS 鐩告瘮鍏堝墠鐨?00澶氱 鏄劇劧鏄揩浜?jiǎn)寰堝?銆傘傘?br>
#include<iostream>
#include<algorithm>
#include <vector>
#include <functional>
using namespace std;
const int maxn = 3000+10;
int data[maxn];
//int re[maxn*maxn/2];
bool cmp(int a,int b)
{
return a>b;
}
int main()
{
int N,M,ans,i;
vector<int > re(maxn*maxn/2);
while(scanf("%d%d",&N,&M)!=EOF)
{
for(i = 0; i < N; i ++)
scanf("%d",&data[i]);
//sort(data,data+N,cmp);
ans = 0;
for( i = 0;i < N;i++)
for(int j = i+1;j<N;j++)
{
re[ans] = data[i]+data[j];
//re.p (data[i]+data[j]);
ans ++;
}
//for( vector<int>::iterator it1 = re.begin(); it1 != re.end() ; it1 ++)
// cout<<*it1<<" ";
//printf("\n");
//partial_sort(re.begin(),re.begin()+M,re.end());//鍥犱負(fù)鐢寵浜?jiǎn)axn*maxn/2 絀洪棿 鎵浠ユ湁寰堝鏄?鍊?nbsp;
/* 榪欐槸瀵艱嚧鎺掑簭鍚?nbsp;鍑虹幇0 鍊肩殑鍘熷洜*/
partial_sort(re.begin(),re.begin()+M,re.begin()+ans,cmp);
for( vector<int>::iterator it = re.begin(); it != re.begin()+M&& it != re.end() ; it ++)
if(it ==re.begin()) cout<<*it;
else cout<<" "<<*it;
cout<<endl;// printf("\n");
}
return 0;
}
]]>
#include<iostream>
#include<algorithm>
using namespace std;
const int maxn = 3000+10;
int data[maxn];
int re[maxn*maxn/2];
bool cmp(int a,int b)
{
return a>b;
}
int main()
{
int N,M,ans;
while(scanf("%d%d",&N,&M)!=EOF)
{
for(int i = 0; i < N; i ++)
scanf("%d",&data[i]);
//sort(data,data+N,cmp);
ans = 0;
for( i = 0;i < N;i++)
for(int j = i+1;j<N;j++)
{
re[ans++] = data[i]+data[j];
}
sort(re,re+N*(N-1)/2,cmp);
for( i = 0; i < M; i ++)
printf(i ==0 ?"%d":" %d",re[i]);
printf("\n");
}
return 0;
}
鍋欰CM棰樼殑鏃跺欙紝鎺掑簭鏄竴縐嶇粡甯歌鐢ㄥ埌鐨勬搷浣溿傚鏋滄瘡嬈￠兘鑷繁鍐欎釜鍐掓場(chǎng)涔嬬被鐨凮(n^2)鎺掑簭錛屼笉浣嗙▼搴忓鏄撹秴鏃訛紝鑰屼笖嫻垂瀹濊吹鐨勬瘮璧涙椂闂達(dá)紝榪樺緢鏈夊彲鑳藉啓閿欍係TL閲岄潰鏈変釜sort鍑芥暟錛屽彲浠ョ洿鎺ュ鏁扮粍鎺掑簭錛屽鏉傚害涓簄*log2(n)銆備嬌鐢ㄨ繖涓嚱鏁幫紝闇瑕佸寘鍚ご鏂囦歡銆?br> 榪欎釜鍑芥暟鍙互浼犱袱涓弬鏁版垨涓変釜鍙傛暟銆傜涓涓弬鏁版槸瑕佹帓搴忕殑鍖洪棿棣栧湴鍧錛岀浜屼釜鍙傛暟鏄尯闂村熬鍦板潃鐨勪笅涓鍦板潃銆備篃灝辨槸璇達(dá)紝鎺掑簭鐨勫尯闂存槸[a,b)銆傜畝鍗曟潵璇達(dá)紝鏈変竴涓暟緇刬nt a[100]錛岃瀵逛粠a[0]鍒癮[99]鐨勫厓绱犺繘琛屾帓搴忥紝鍙鍐檚ort(a,a+100)灝辮浜?jiǎn)锛岄粯璁ょ殑鎺掑簭鏂瑰紡鏄崌搴忋?br> 鎷挎垜鍑虹殑“AC鐨勭瓥鐣?#8221;榪欓鏉ヨ錛岄渶瑕佸鏁扮粍t鐨勭0鍒發(fā)en-1鐨勫厓绱犳帓搴忥紝灝卞啓sort(t,t+len);
瀵瑰悜閲弙鎺掑簭涔熷樊涓嶅錛宻ort(v.begin(),v.end());
鎺掑簭鐨勬暟鎹被鍨嬩笉灞闄愪簬鏁存暟錛屽彧瑕佹槸瀹氫箟浜?jiǎn)灏忎簬杩惤帡鐨劸c誨瀷閮藉彲浠ワ紝姣斿瀛楃涓茬被string銆?br> 濡傛灉鏄病鏈夊畾涔夊皬浜庤繍綆楃殑鏁版嵁綾誨瀷錛屾垨鑰呮兂鏀瑰彉鎺掑簭鐨勯『搴忥紝灝辮鐢ㄥ埌絎笁鍙傛暟鈥斺旀瘮杈冨嚱鏁般傛瘮杈冨嚱鏁版槸涓涓嚜宸卞畾涔夌殑鍑芥暟錛岃繑鍥炲兼槸bool鍨嬶紝瀹冭瀹氫簡(jiǎn)浠涔堟牱鐨勫叧緋繪墠鏄?#8220;灝忎簬”銆傛兂鎶婂垰鎵嶇殑鏁存暟鏁扮粍鎸夐檷搴忔帓鍒楋紝鍙互鍏堝畾涔変竴涓瘮杈冨嚱鏁癱mp
bool cmp(int a,int b)
{
return a>b;
}
鎺掑簭鐨勬椂鍊欏氨鍐檚ort(a,a+100,cmp);
鍋囪鑷繁瀹氫箟浜?jiǎn)涓涓粨鏋勪綋node
struct node{
int a;
int b;
double c;
}
鏈変竴涓猲ode綾誨瀷鐨勬暟緇刵ode arr[100]錛屾兂瀵瑰畠榪涜鎺掑簭錛氬厛鎸塧鍊煎崌搴忔帓鍒楋紝濡傛灉a鍊肩浉鍚岋紝鍐嶆寜b鍊奸檷搴忔帓鍒楋紝濡傛灉b榪樼浉鍚岋紝灝辨寜c闄嶅簭鎺掑垪銆傚氨鍙互鍐欒繖鏍蜂竴涓瘮杈冨嚱鏁幫細(xì)
浠ヤ笅鏄唬鐮佺墖孌碉細(xì)
bool cmp(node x,node y)
{
if(x.a!=y.a) return x.a
if(x.b!=y.b) return x.b>y.b;
return return x.c>y.c;
}
]]>