本文共 1681 字，大约阅读时间需要 5 分钟。

线段树：

/*#define maxn 1000005int gnode[maxn];long long gnum[maxn*4];the segment gnum must full binary tree,the left child is loc*2+1,and the right child is loc*2+2.*/void GxdSegmentTreeAdd(long long* gnum,int glen,int gfl,int gfr,int gnow,int gkeyloc){    gnum[gnow]++;    if(gfl==gfr) return ;    int mid = (gfl+gfr)/2;    if(gkeyloc>mid) GxdSegmentTreeAdd(gnum,glen,mid+1,gfr,gnow*2+2,gkeyloc);    else GxdSegmentTreeAdd(gnum,glen,gfl,mid,gnow*2+1,gkeyloc);}long long GxdSegmentTreeSearch(long long* gnum,int glen,int gfl,int gfr,int gnow,int gkeyl,int gkeyr){    if(gfl==gkeyl&&gfr==gkeyr) return tree[gnow];    int mid = (gfl+gfr)/2;    if(gkeyl>mid) return GxdSegmentTreeSearch(gnum,glen,mid+1,gfr,gnow*2+2,gkeyl,gkeyr);    else if(gkeyr<=mid) return GxdSegmentTreeSearch(gnum,glen,gfl,mid,gnow*2+1,gkeyl,gkeyr);    else return GxdSegmentTreeSearch(gnum,glen,gfl,mid,gnow*2+1,gkeyl,mid)+GxdSegmentTreeSearch(gnum,glen,mid+1,gfr,gnow*2+2,mid+1,gkeyr);}

结构体排序：

struct Node{    int c;    int v;};Node num[maxn];int cmp(const void* a,const void* b){    Node *x = (Node*)a;    Node *y = (Node*)b;    return x->v - y->v; //ascend sort}qsort(num,n,sizeof(num[0]),cmp);

Vector容器迭代：

vector
   
     cnt;string ansstr;for(auto str:cnt){    if(ans[str] > maxnum)    {        maxnum = ans[str];        ansstr = str;    }}
   

运算符重载：

struct Pallet{public:    int l;    int w;public:    void init(int a,int b){l=max(a,b);w=min(a,b);}    bool operator == (const Pallet& t){
  if(t.l==l&&t.w==w) return true;return false;}};

重定向：

#ifdef LOCAL    freopen("input.txt","r",stdin);    freopen("output.txt","w",stdout);    fclose(stdin);    fclose(stdout);#endif

整行读取：

//使用fgets（buf，maxn，stdin）；来读取一整行

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