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| class Solution {
public boolean isNumber(String s) {
boolean hasDot = false, hasNumber = false;
for (int i = getNumStartIndex(s, 0); i < s.length(); i++) {
char c = s.charAt(i);
if (c == 'e' || c == 'E') {
if (!hasNumber) {
return false;
}
return isInt(s, i + 1);
} else if (c >= '0' && c <= '9') {
hasNumber = true;
} else if (c == '.') {
if (!hasDot) {
hasDot = true;
} else {
return false;
}
} else {
return false;
}
}
return hasNumber;
}
private int getNumStartIndex(String s, int i) {
if (i == s.length()) {
return i;
}
char c = s.charAt(i);
return c == '+' || c == '-' ? i + 1 : i;
}
private boolean isInt(String s, int i) {
i = getNumStartIndex(s, i);
if (i == s.length()) {
return false;
}
while (i < s.length()) {
char c = s.charAt(i);
if (c < '0' || c > '9') {
return false;
}
i++;
}
return true;
}
}
|