排序,双指针扫一遍

排序,双指针扫一遍

string a, b;
cin >> a >> b;
sort(a.begin(), a.end());                 //排序
sort(b.begin(), b.end());

int pa = 0, pb = 0;
n = a.size(), m = b.size();

while(pa<n && pb<m) {                     //双指针扫一遍
    if(a[pa] == b[pb])                    //相同一起往下指
        pa ++, pb ++;
    else                                  //不同b往下指
        pb ++;
}
printf("%s\n", pa==n ? "true" : "false"); //能够构造出a

完整代码

#define debug
#ifdef debug
#include <time.h>
#include "/home/majiao/mb.h"
#endif

#include <iostream>
#include <algorithm>
#include <vector>
#include <string.h>
#include <map>
#include <set>
#include <stack>
#include <queue>
#include <math.h>

#define MAXN ((int)1e5+7)
#define ll long long 
#define INF (0x7f7f7f7f)
#define fori(lef, rig) for(int i=lef; i<=rig; i++)
#define forj(lef, rig) for(int j=lef; j<=rig; j++)
#define fork(lef, rig) for(int k=lef; k<=rig; k++)
#define QAQ (0)

using namespace std;

#define show(x...) \
    do { \
        cout << "\033[31;1m " << #x << " -> "; \
        err(x); \
    } while (0)

void err() { cout << "\033[39;0m" << endl; }
template<typename T, typename... A>
void err(T a, A... x) { cout << a << ' '; err(x...); }

namespace FastIO {

    char print_f[105];
    void read() { }
    void print() { putchar('\n'); }

    template <typename T, typename... T2>
        inline void read(T &x, T2 &... oth) {
            x = 0;
            char ch = getchar();
            ll f = 1;
            while (!isdigit(ch)) {
                if (ch == '-') f *= -1; 
                ch = getchar();
            }
            while (isdigit(ch)) {
                x = x * 10 + ch - 48;
                ch = getchar();
            }
            x *= f;
            read(oth...);
        }
    template <typename T, typename... T2>
        inline void print(T x, T2... oth) {
            ll p3=-1;
            if(x<0) putchar('-'), x=-x;
            do{
                print_f[++p3] = x%10 + 48;
            } while(x/=10);
            while(p3>=0) putchar(print_f[p3--]);
            putchar(' ');
            print(oth...);
        }
} // namespace FastIO
using FastIO::print;
using FastIO::read;

int n, m, Q, K;


int main() {
#ifdef debug
    freopen("test", "r", stdin);
    // freopen("out_main", "w", stdout);
    clock_t stime = clock();
#endif
    string a, b;
    cin >> a >> b;
    sort(a.begin(), a.end());                 //排序
    sort(b.begin(), b.end());

    int pa = 0, pb = 0;
    n = a.size(), m = b.size();

    while(pa<n && pb<m) {                     //双指针扫一遍
        if(a[pa] == b[pb])                    //相同一起往下指
            pa ++, pb ++;
        else                                  //不同b往下指
            pb ++;
    }
    printf("%s\n", pa==n ? "true" : "false"); //能够构造出a




#ifdef debug
    clock_t etime = clock();
    printf("rum time: %lf 秒\n",(double) (etime-stime)/CLOCKS_PER_SEC);
#endif 
    return 0;
}