Submission #1355620

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Source Code Expand

#include <bits/stdc++.h>

using namespace std;

using ll = long long;
using vi = vector<int>;
using db = double;
#define pb push_back

// 看了题解，发现当时想不出的原因主要不是倍长，而是倍长的前一步的DP没想清楚

const int mxn = 500006;
const int emp = 26;

char a[mxn];
int n;
int f[mxn][27]; // 无效均为0
int s[mxn][20];

int main() {
	scanf("%s", a + 1);
	n = strlen(a + 1);
	for (int i = 1; i <= n; ++i)
		a[i] -= 'a';
	
	for (int i = n; i >= 1; --i) {
		f[i][a[i]] = i + 1;
		for (int j = a[i] + 1; j <= 26; ++j)
			f[i][j] = f[f[i][j - 1]][j - 1];
		for (int j = 0; j < a[i]; ++j)
			f[i][j] = f[f[i][emp]][j];
	}
	
	for (int i = n; i >= 1; --i) {
		s[i][0] = f[i][emp];
		for (int j = 1; j < 20; ++j)
			s[i][j] = s[s[i][j - 1]][j - 1];
	}
	
	int q;
	cin >> q;
	while (q--) {
		int l, r;
		scanf("%d%d", &l, &r);
		++r;
		for (int i = 20; i--; ) if (s[l][i] && s[l][i] <= r)
			l = s[l][i];
		puts(l == r ? "Yes" : "No");
	}
	
	return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:21:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%s", a + 1);
                    ^
./Main.cpp:44:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d", &l, &r);
                        ^

Judge Result